Ubiquitous Talk

Sun’s S7000 Storage Systems with Fishworks is Really Awesome

 

I came across Brendan Gregg’s blog and found this entry http://blogs.sun.com/brendan/entry/unusual_disk_latency to be really interesting. He demonstrates how powerful Fishworks analytics really are. This is a great example of what capability Dtrace and the Fishworks application brings to the storage platform. It’s a cool demo and I encourage you to have a look at what this Open Storage product can do.

Regards,

 

Mike

Site Contents: © 2009  Mike La Spina

ZFS Snapshot Rollup Bash Script

Site Contents: © 2008  Mike La Spina

Provisioning Disaster Recovery with ZFS, iSCSI and VMware

OpenSolaris, ZFS, iSCSI and VMware are a great combination for provisioning Disaster Recovery (DR) systems at exceptionally low cost. There are some fundamentally well suited features of ZFS and VMFS volumes that provide a relatively simply and very efficient recovery process for VMware hosted non-zero RPO crash consistent recovery based environments. In this weblog I will demonstrate this capability and provide some step by step howto’s for replicating a ZFS, iSCSI and VMFS VMware based environment securely over a WAN or whatever you may have to a single ESXi remote server hosting a child OpenSolaris VM which provisions ZFS and iSCSI VMFS LUN’s to the parent ESXi host. The concept is to wrap the DR services into a single low cost self contained DR box that can be expanded out in the event of an actual DR incident while allowing for regular testing and validation processing without the high costs normally associated with standby DR systems. As one would expect this method becomes a very appealing solution for small to medium businesses who would normally abstain from DR provisioning activity due to the inherently high cost and complexity of DR.

The following diagram illustrates this DR system architecture.

 

 

When we have VMFS volumes backed by iSCSI based ZFS targets we gain the powerful replication capability of ZFS send and receive commands. This ZFS feature procures the ability to send an entire VMFS volume by way of a raw iSCSI target ZFS backing store. And once sent initially we can base all subsequent sends as a delta of change from a previous send snapshot which are respectively referred as snapshot deltas. Thus if we initially snapshot an iSCSI backing store and send the stream to a remote ZFS file system we can then send all the changed object data from that previous snapshot point to the current snapshot point and whatever else may be in between those snapshots. The result is a constant update of VMFS changes from the source ZFS file system to the remote ZFS file system of which can be completely different hardware. This ZFS hardware autonomy gift allows us to provision a much lower cost system on the DR remote side to host the VMFS volumes. For example the target system which is presented in this weblog is an IBM x3500 and the source is a SUN X4500 detailed in a previous blog.

There are some important considerations that should be kept in mind when we use snapshots to create any DR process. One of the most important areas to consider is the data change rates on the VMFS volumes that are to be included in the DR send/receive process. When we have VMware servers or VM’s that have low memory allocations (a.k.a. over committed memory) or application behaviors that swap to disk frequently we will observe high volumes of what I call disk noise or disk data change that has no permanent value. High amounts of disk noise will consume more storage and bandwidth on both systems when snapshots are present. In cases where the disk noise reaches a rate of 1GB/Day or more per volume it would be prudent to isolate the noise sources on a VMFS volume that will not be part of the replication strategy. You could for example create a VMFS LUN for swap and temp files on the local ESX host which can be ignored in the replication scope. Another important area is the growth rate of the overall storage may require routine pruning of older snapshots to reduce the total consumption of disk. For example if we have high change rates from database sources which can not be isolated we can at monthly intervals destroy all but one of the last months snapshots to conserve the available storage on both systems. This method still provisions a good DR process and as well provides a level of continuous data protection (CDP) and is simmilar to a grandfather/father/son preservation scheme.

Since we are handling valuable information we must use secure methods to access and handle the data transfers. This can be provisioned by using ssh and dedicated service accounts that will perform this one specific function. ZFS send and receive functions use an inherently secure approach by employing ssh as a transport tunnel when transmitting storage data to the target ZFS file system. This is just what we need to provision a secure exchange to a DR environment. Conversly we could use IPSec but this would be significantly more complex to achieve and complexity is not a good this when short implementation time is a priority.With this explanation wrapped up in our minds lets begin some of the detailed tasks that are required to procure this real world DR solution.

ESXi Server  

The DR VMware server is based on the free ESXi product and with this we can encapsulate the entire DR functionallity in one server hardware platform. Within the ESXi engine we need to install and configure an OpenSolaris 5.11 snv_98 or higher VM using VMFS as the storage provider. This ESXi server configuration consists of a single SATA boot LUN and this LUN also stores the OpenSolaris iSCSI VM. In addition to the boot LUN we will create the ZFS iSCSI stores on serveral additional SATA disks that are presented to the OpenSolaris VM as separate VMFS datastores which we will use to create large vmdk’s. The virtual vmdk disks will be assigned as vdev’s for our receiving ZFS zpool. Talk about rampent layering. At this point we have a OpenSolaris VM defined on a hardware platform on which OpenSolaris would normally never work with natively in this example. You have goto love what you can do with VMware virtualization. By the way when SUN’s xVM product is more mature it could provision the same fuctionallity with native ZFS provisioning and that alone really is worth a talk, but lets continue our focus on this platform for now.

There are many configuration options available on the network provisioning side of our ESXi host. In this case VLAN’s are definetly a solid choice for this application and is my prefered approach to controlling iSCSI data flow. We initially would only need to provide iSCSI access for the local OpenSolaris VM as this will provision a virtual SAN to the parent ESXi host. The parent ESXi host needs to be able mount the iSCSI target LUN’s that were available in the production environmant and validate that the DR process works. In the event of DR activation we would need to add external ESXi hosts and VLAN’s will provide both locally isolated iSCSI networks with easy expansion if these services are required externally all with out need to purchase external switch hardware for the system until it is required. Thus within the ESXi host we need to define a VLAN for the iSCSI SAN and an isolated VLAN for production VM validations and finally we need to define the replication and management network which can optionally use a VLAN or be untagged depending on your environment.

This virtualized DR environment grants advanced capabilties to perform rich system tests at commodity prices. Very attracive indeed. For example you can now clone the replicated VMFS LUN’s on the DR engine and with a liitle Solaris SMF iSCSI target service magic provision the clone as a duplicated ESX environment which does not impact the ongoing replication. As well we have network isolation and virtualization that allows the environment to exist in a closed fully functional remotely accessible world. This world can also be extended out as a production mirror test environment with dynamic revert back in time and repeat functionallity.

There are many possible ESXi network and disk configurations that would meet the DR server’s requirements. At the minimum we should provision the following elements.

•  Provision a bootable single separate SATA disk with a minimum of 16G available for the VMFS LUN that will store the OpenSolaris iSCSI VM.
•  Provision a minimum of three (optimally six) additional SATA disks or more if required as VMFS LUN’s to host the ZFS zpool vdev’s with vmdk’s.
•  Provision a minimum of two 1Gb Ethernet adaptors, teamed would be preferable if more are available.
•  Define vSwitch0 with a VLAN tagged VM Network portgroup to connect the replication side of the OpenSolaris iSCSI VM and a Service Console portgroup to manage the ESXi host.
•  Define vSwitch1 with a VLAN tagged iSCSI VM kernel portgroup to service the iSCSI data plane and also define a VM Network portgroup on the same VLAN to connect with the target interface of the OpenSolaris iSCSI VM.
•  Define the required isolated VLAN tagged identically named portgroups  as production on vSwitch0 and use a separated VLAN numbering set for them for isolation.
•  Define the OpenSolaris VM with one adapter to connected to the production network portgroup and one adapter to attached to the iSCSI data plane portgroup to serve the iSCSI target IP.

Here is an example of what the VM disk assignments should look like.

Once the ESXi server is successfully built and the Opensolaris iSCSI VM is installed and functional we can create the required elements for enabling ZFS replication.

Create Service Accounts

On the systems that will act as replication partners create zfsadm ID’s as service accounts using the provided commands.

# useradd -s /usr/bin/bash -d /export/home/zfsadm -P ‘ZFS File System Management’ zfsadm
# mkdir /export/home/zfsadm
# mkdir /export/home/zfsadm/backup
# cp /etc/skel/* /export/home/zfsadm
# echo PATH=/usr/bin:/usr/sbin:/usr/ucb:/etc:. > /export/home/zfsadm/.profile
# echo export PATH >> /export/home/zfsadm/.profile
# chown –R zfsadm /export/home/zfsadm
# passwd zfsadm

Note the parameter -P ‘ZFS File System Management’, This will grant the account an RBAC profile association to administratively manage our ZFS file system unlike root which is much too powerful and is all to often used by many of us. 

The next step is to generate some crypto keys for ssh connectivity we start this with a login as the newly created zfsadm user and run a secure shell locally to ensure you have a .ssh directory and key files created in the home drive for the zfsadm user. Note this directory is normally hidden. 

# ssh localhost
The authenticity of host ‘localhost (127.0.0.1)’ can’t be established.
RSA key fingerprint is 0c:aa:64:72:84:b5:04:1c:a2:d0:42:8e:9f:4e:09:9d.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added ‘localhost’ (RSA) to the list of known hosts.
Password:
# exit

Now that we have the .ssh directory we can create a crypto key pair and configure a relatively secure login without the need to enter a password for the remote host using this account.

Do not enter a passphrase, it needs to be blank.

# ssh-keygen -t dsa
Generating public/private dsa key pair.
Enter file in which to save the key (/export/home/zfsadm/.ssh/id_dsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /export/home/zfsadm/.ssh/id_dsa.
Your public key has been saved in /export/home/zfsadm/.ssh/id_dsa.pub.
The key fingerprint is:
bf:58:7b:97:8d:b5:d2:31:26:14:4c:9f:ce:72:a7:20 zfsadm@ss1

The id_dsa file should not be exposed outside of this directory as it contains the private key of the pair, only the public key file id_dsa.pub needs to be exported. Now that our key pair is generated we need to append the public portion of the key pair to a file named authorized_keys2. 

# cat $HOME/.ssh/id_dsa.pub >> $HOME/.ssh/authorized_keys2

Repeat all the Create Service Accounts steps and crypto key steps on the remote server as well.

We will use the Secure Copy command to place the public key file on each opposing hosts zfsadm users home directory so that when the ssh tunnel is started the remote host can decrypt the encrypted connection request completing the tunnel which is generated with the private part of the pair. This is why we must protect the private part of the pair from exposure. Granted we have also defined an additional layer of security here by defining a dedicated user for the ZFS send activity it is very important that the private key is secured properly and it is not necessary to back it up as you can regenerate them if required.

From the local server here named ss1 (The remote server is ss2)

# scp $HOME/.ssh/id_dsa.pub ss2:$HOME/.ssh/ss1.pub
Password:
id_dsa.pub      100% |**********************************************|   603       00:00
# scp ss2:$HOME/.ssh/id_dsa.pub $HOME/.ssh/ss2.pub
Password:
id_dsa.pub      100% |**********************************************|   603       00:00
# cat $HOME/.ssh/ss2.pub >> $HOME/.ssh/authorized_keys2

And on the remote server ss2

# ssh ss2
password:
# cat $HOME/.ssh/ss1.pub >> $HOME/.ssh/authorized_keys2
# exit

This completes the trusted key secure login configuration and you should be able to secure shell from either system to the other without a password prompt using the zfsadm account. To further limit security exposure we could employe ipaddress restrictions and as well enable a firewall but this is beyond the scope of this blog.

 Target Pool and ZFS rights

As a prerequisite you need to create the receiving zpool on the target to allow the zfs sends to occur. The receiving zpool name should be the same as the source to allow ease in the re-serving of iSCSI targets. Earlier we granted the “ZFS File System Management” profile to this zfsadm user. This RBAC profile allows us to run a pfexec command which pre checks what profiles the user is assigned and then executes appropriately based on this assignment. The bonus here is you do not have to create granular rights assignments to the ZFS file system.

On the target server create your receiveing zpool.

# zpool create rp1 <your vdev’s>

Create a Cron Job

Using a cron job we will invoke our ZFS snapshots and send tasks to the target host with the execution of a bash script named zfs-daily.sh. We need to use the crontab command to create a job that will execute it as the zfsadm user, no other user except root can access this job and that a good thing considering it has the ability to shell to another host!

As root add the zfs user name to the /etc/cron.d/cron.allow file.

# echo zfsadm >> /etc/cron.d/cron.allow
# crontab –e zfsadm
59 23 * * * ./zfs-daily.sh zfs-daily.rpl

Hint: crontab uses vi – http://www.kcomputing.com/kcvi.pdf  “vi cheat sheet”

The key sequence would be hit “i” and key in the line then hit “esc :wq” and to abort “esc :q!”

Be aware of the timezone the cron service runs under, you should check it and adjust it if required. Here is a example of whats required to set it. 

# pargs -e `pgrep -f /usr/sbin/cron`

8550:   /usr/sbin/cron
envp[0]: LOGNAME=root
envp[1]: _=/usr/sbin/cron
envp[2]: LANG=en_US.UTF-8
envp[3]: PATH=/usr/sbin:/usr/bin
envp[4]: PWD=/root
envp[5]: SMF_FMRI=svc:/system/cron:default
envp[6]: SMF_METHOD=start
envp[7]: SMF_RESTARTER=svc:/system/svc/restarter:default
envp[8]: SMF_ZONENAME=global
envp[9]: TZ=PST8PDT

Let’s change it to CST6CDT

# svccfg -s system/cron:default setenv TZ CST6DST

Also the default environment path for cron may cause some script “command not found” issues, check for a path and adjust it if required.

# cat /etc/default/cron
#
# Copyright 1991 Sun Microsystems, Inc.  All rights reserved.
# Use is subject to license terms.
#
#pragma ident   “%Z%%M% %I%     %E% SMI”
CRONLOG=YES

This one has no default path, add the path using echo.

# echo PATH=/usr/bin:/usr/sbin:/usr/ucb:/etc:. > /etc/default/cron
# svcadm refresh cron
# svcadm restart cron 

Create Snapshot Replication Script

Here is the link for the zfs-daily.sh replication script you will need to grant exec rights to this file e.g.

# chmod 755 zfs-daily.sh 

The replcation script needs to live in the zfsadm home directory /export/home/zfsadm at this point I only have the one script built but other ones are in the works like a grandfather/father/son snapshot rollup script. The first run of the script can take a considerable amount of time depending on the available bandwidth and size of the VMFS luns. This cron job runs at midnight and took 6 hours over 100MB’s of bandwidth the first time and less that 5 min thereafter. A secondary script that runs hourly and is rolled up at days end would be beneficial. I will get it around to that one and the grandfather/father/son script later.

At this point we have an automated DR process that provides a form of CDP. But we do not have a way to access it so we need to perform some additional steps. In order for VMware to use the relocated VMFS iSCSI targets we need to reinstate some critical configuration info that was stored on the source Service Management Facility (SMF) repository. Within the iscsitgtd service properties we have the Network Address Authority (NAA) value which is named GUID in the properties list. This value is very important, when a VMFS is initialized the NAA is written to the VMFS volume header and this will need to be redefined on the DR target so that VMware will recognize the data store as available. If the NAA on the header and target do not match, the volume will not be visible to the DR VMware ESXi host. To protect this configuration info we need to export it from the source host and send it to the target host.

Export SMF iSCSI configuration

The iscstgtd service configuration elements can be easily exported using the following  command.

# svccfg export iscsitgt > /export/home/zfsadm/backup/ss1-iscsitgt.xml
 

# scp ss1:/export/home/zfsadm/backup/* ss2:/export/home/zfsadm/backup/

SMF iscsitgt import and iSCSI configuration details

To import the production service we would issue the following commands.

# svcadm disable iscsitgt
# svccfg delete iscsitgt
# svccfg import /export/home/zfsadm/backup/ss1-iscsitgt.xml

Importing the iscsitgt service configuration is a simple task but it does have some elements that will be problematic if they are left unchecked. For example iSCSI Target Portal Group Tag values are included with the exported/inport function and thus you may need to change the portal groups values to correct discovery failure when the ip addresses are different on the target system. Another potential issue is leaving the existing SMF config in place and then importing the new one on top of it. This is not a best practice as you may create an invalid SMF for the iscsitgt service with elements that are orphaned out etc. The SMF properties will have the backing store path from the source server and if the target server does not have the same zpool name this will need to be fixed. And lastly make sure you have the same iscsitgtd version on each end since it will have potential changes between the versions.

You will also need to add the ESXi software initiator to the iSCSI target(s) on the receiving server and grant access with an acl entry and chap info if used.

# iscsitadm create initiator –iqn iqn.1998-01.com.vmware:vh0.0 vh0.0
# iscsitadm modify target –acl vh0.0 ss1-zstore0

To handle a TPGT configuration change its simply a matter of re-adding them with the iscsitadm utility as demonstrated here or possibly deleting the one that are not correct.

# iscsitadm create tpgt 1
# iscsitadm modify tpgt -i 10.10.0.1 1
# iscsitadm modify tpgt -i 10.10.0.2 1
# iscsitadm modify target -p 1 ss1-zstore0

To delete a tpgt that is not correct is very strait forward.

# iscsitadm delete target -p 1 ss1-zstore0
# iscsitadm delete tpgt -A 1

Where 10.20.0.1 and 2 are the target interfaces that should participate in portal group 1 and ss1-zstore0 is the target alias. In some cases you may have to remove the tpgt  all together. The backing store is editable as well as many other SMF properties. To change a backing store value in the SMF we use the svccfg command as follows.

Here is an example of listing all the backing stores and then changing the /dev/zvol/rdsk/sp2/iscsi/lun0 so its on zpool sp1 instead of sp2

# svcadm enable iscsitgt
# svccfg -s iscsitgt listprop | grep backing-store

param_dr-zstore0_0/backing-store                astring  /dev/zvol/rdsk/sp2/iscsi/lun0
param_dr-zstore0_1/backing-store                astring  /dev/zvol/rdsk/sp1/iscsi/lun1

# svccfg -s iscsitgt setprop param_dr-zstore0_0/backing-store=/dev/zvol/rdsk/sp1/iscsi/lun0
# svccfg -s iscsitgt listprop | grep backing-store

param_dr-zstore0_0/backing-store                astring  /dev/zvol/rdsk/sp1/iscsi/lun0
param_dr-zstore0_1/backing-store                astring  /dev/zvol/rdsk/sp1/iscsi/lun1

Changing the backing store value is instrumental if you wish to mount the VMFS LUN’s to provision system validation or online testing. However do not attach the  file system from the active replicated zfs backing store to the ESXi server for validation or testing as it will fail any additional replications once it is modified outside of the active replication stream. You must first create a clone of a chosen snapshot and then modify the backing store to use this new backing store path. This method will present a read/write clone through the iscsitgt service and will have the same iqn names so no reconfiguration would be required to create different time windows into the data stores or reversion to a previous point.

Here is an example of how  this would be accomplished.

# zfs create sp1/iscsi/clones
# zfs clone sp1/iscsi/lun0@10-10-2008-23:45 sp1/iscsi/clones/lun0
# svcadm refresh iscsitgt
# svcadm restart iscsitgt

To change to a different snapshot time you would simply need to destroy or rename  the current clone and replace it with a new or renamed clone of an existing snapshot on the same clone backing store path.

# zfs destroy sp1/iscsi/clones/lun0
# zfs clone sp1/iscsi/lun0@10-11-2008-23:45 sp1/iscsi/clones/lun0
# svccfg -s iscsitgt setprop param_dr-zstore0_0/backing-store=/dev/zvol/rdsk/sp1/iscsi/clones/lun0
# svcadm refresh iscsitgt
# svcadm restart iscsitgt

VMware Software iSCSI configuration

The ESXi iSCSI software configuration is quite strait forward. In this architecture we need to place an interface of the OpenSolaris iSCSI target host on vSwitch1 which is where we defined the iSCSI-Net0 VM kernel network. To do this we create a VM Network portgroup on the same VLAN ID as the iSCSI VM kernel interface.

Here is an example of what this configuration looks like.

For more deatail on how to configure the iSCSI VM interfaces see this blog http://blog.laspina.ca/ubiquitous/running_zfs_over_iscsi_as in this case you would not need to define an aggregate since there is only one interface for the iSCSI vSAN.

The final step in the configuration is to define a discovery target on the iSCSI software configuration panel and then rescan the vmhba for new devices.

Hopefully this blog was of interest for you.

Til next time….

Mike

Site Contents: © 2008  Mike La Spina

X4500 ZFS and iSCSI Performance Characteristics

Benchmarks are useful in many ways, they are particularly effective when you wish to validate an architectural design. In this case a SUN X4500 as an iSCSI target and VMware ESX 3.5 servers with QLA4050c initiators. This benchmark is not a definitive measure of what the architectural maximums are for the X4500 or the other components of the architecture, its a validation that the whole system performs as expected under the context of its current configuration. Within this configuration there are several components that have expected limitations such as the Ethernet switch buffering and flow control rates. As well we need to realize that in any iSCSI configuration it will have a characteristic collapsing point and inherent latency due to packet saturation peeks. In this architecture we can expect several specific limits such as 60% effective 1Gb Ethernet connection usage limits before latency issues are prevalent. Additionally when using SATA disk interfaces we can expect that high rates of small I/O will result in less than effective performance characteristics in the event that this behavior is sustained or is occurring very frequently.

The design details are on blog entry http://blog.laspina.ca/ubiquitous/running_zfs_over_iscsi_as

What becomes important to consider with this architecture is the cost to performance ratio in which this design is very attractive. The combined components of this system perform very well in this context and it has some pleasant surprises within its delivered capabilities. When we look at the performance of this design there are elements that seem to escape the traditional behaviors of some of the involved subcomponents.  Within the current limiting parameters we would expect it to underperform in more use cases that not, but this behavior is not occurring. There are several reasons for this result and ZFS is a big factor within the system since it performs blocks of  transactional write functions which are complimentary to SATA interface behaviors. SATA interfaces work well with larger transfer segments rather than small short transfer operations and thus ZFS optimizes performance over SATA disk arrays. Another factor is the virtualization layer on the VMware hosts consolidates many of the smaller I/O behaviors and delivers larger read and write transfer requests, provided that we make use of vmdk files when provisioning virtual disk devices.

In the first graph we are observing the results of a locally executed dd command collected with iostat as follows:

dd if=/dev/zero of=/rp1/iscsi/iotest count=1024k bs=64k

iostat -x 15 13 (only the last 12 outputs are used for the graph plot)

 

The graph reveals excellent 36 disk raid Z write performance at a level of 600MB/s for a sustained time period of 3 Min.

Other raid modes can provide significantly superior performance such as a 24 pair raid 1 mirror,  this however does not grant the optimal use of the possible available disk capacity and is not required for this application.

 

 

 

This next graph reveals excellent read performance at a level of 800MB/s for a sustained time period of 3 Min. A dd command was again used as follows:

dd if=/rp1/iscsi/iotest of=/dev/null count=1024k bs=64k

             

 

Site Contents: © 2008  Mike La Spina

Running ZFS over iSCSI as a VMware vmfs store

The first time I looked at ZFS it totally floored me. This is a file system that has changed storage system rules as we currently know them and continues to do so. It is with no doubt the best architecture to date and now you can use it for your VMware stores.

Previously I had explored using it for a VMware store but ran into many issues which were real show stoppers. Like the VPD page response issue which made VMware see only one usable iSCSI store. But things are soon to be very different when Sun releases the snv_93 or above to all. I am currently using the unreleased snv_93 iscsitgt code and it works with VMware in all the ways you would want. Many thanks to the Sun engineers for adding NAA support on the iSCSI target service. With that being said let me divulge the details and behaviors of the first successful X4500 ZFS iSCSI VMware implementation in the real world.

Lets look at the Architectural view first.

 
The architecture uses a best practice approach consisting of completely separated physical networks for the iSCSI storage data plane. All components have redundant power and network connectivity. The iSCSI storage backplane is configured with an aggregate and is VLAN’d off from the server management network. Within the physical HP 2900’s an inter-switch ISL connection is defined but is not critical. This allows for more available data paths if additional interfaces were assigned on the ESX host side.
The Opensolaris aggregate and network components are configured as follows:

For those of you using Indiana….By default nwam is enabled on Indiana and this needs to be disabled and the physical network service enabled.

svcadm disable svc:/network/physical:nwam
svcadm enable svc:/network/physical:default

The aggregate is defined using the data link adm utility but first any bindings need to be cleared by unplumbing the interfaces.

e.g. ifconfig e1000g0 unplumb

Once cleared the assignment of the physical devices is possible using the following commands

dladm create-aggr –d e1000g0 –d e1000g1 –P L2,L3 1
dladm create-aggr –d e1000g2 –d e1000g3 –P L2,L3 2

Here we have set the policy allowing layer 2 and 3 and defined two aggregates aggr1 and aggr2. We can now define the VLAN based interface shown here as VLAN 500 instances 1 are 2 respective of the aggr instances. You just need to apply the following formula for defining the VLAN interface.

(Adaptor Name) + vlan * 1000 + (Adaptor Instance)

ifconfig aggr500001 plumb up 10.1.0.1 netmask 255.255.0.0
ifconfig aggr500002 plumb up 10.1.0.2 netmask 255.255.0.0

To persist the network configuration on boot you will need to create hostname files and hosts entries for the services to apply on startup.

echo ss1.iscsi1 > /etc/hostname.aggr500001
echo ss1.iscsi2 > /etc/hostname.aggr500002

Edit /etc/hosts to have the following host entries.

::1 localhost
127.0.0.1 ss1.local localhost loghost
10.0.0.1 ss1 ss1.domain.name
10.1.0.1 ss1.iscsi1
10.1.0.2 ss1.iscsi2

On the HP switches its a simple static trunk definition on port 1 and 2 using the following at the CLI.

trunk 1-2 trk1 trunk 

Once all the networking components are up and running and persistent, its time to define the ZFS store and iSCSI targets. I chose to include both mirrored and raidz pools. I needed to find and organize the cxtxdx device names using the cfgadm command or you could issue a format command as well to see the controller, target, disk names if you’re not using an X4500. I placed the raidz devices across controllers to improve I/O and distribute the load. It would not be a prudent to place one array on a single SATA controller. So here is what it ends up looking like from the ZFS command view.

zpool create –f rp1 raidz1 c4t0d0 c4t6d0 c5t4d0 c8t2d0 c9t1d0 c10t1d0
zpool add rp1 raidz1 c4t1d0 c4t7d0 c5t5d0 c8t3d0 c9t2d0 c10t2d0
zpool add rp1 raidz1 c4t2d0 c5t0d0 c5t6d0 c8t4d0 c9t3d0 c10t3d0
zpool add rp1 raidz1 c4t3d0 c5t1d0 c5t7d0 c8t5d0 c9t5d0 c11t0d0
zpool add rp1 raidz1 c4t4d0 c5t2d0 c8t0d0 c8t6d0 c9t6d0 c11t1d0
zpool add rp1 raidz1 c4t5d0 c5t3d0 c8t1d0 c8t7d0 c10t0d0 c11t2d0
zpool add rp1 spare c11t3d0
zpool create –f mp1 mirror c10t4d0 c11t4d0
zpool add mp1 mirror c10t5d0 c11t5d0
zpool add mp1 mirror c10t6d0 c11t6d0
zpool add mp1 spare c9t7d0

It only takes seconds to create terabytes of storage, wow it truly is a thing of beauty (geek!). Now it’s time to define a few pools and stores in preparation for the creation of the iSCSI targets. I chose to create units of 750G since VMware would not perform well with much more than that. This is somewhat dependant on the size of the VM and type of I/O but generally ESX host will serve a wide mix so try I keep it to a reasonable size or it ends up with SCSI reservation issues (that’s a bad thing chief).

You must also consider I/O block size before creating a ZFS store this is not something that can be changed later so now is the time. It’s done by adding the –b 64K to the ZFS create command. I chose to use 64k for the block size which aligns with VMWare default allocation size thus optimizing performance. The –s option enables a sparse volume feature aka thin provisioning. In this case the space was available but it is my favorite way to allocate storage.

zfs create rp1/iscsi
zfs create -s -b 64K -V 750G rp1/iscsi/lun0
zfs create -s -b 64K -V 750G rp1/iscsi/lun1
zfs create -s -b 64K -V 750G rp1/iscsi/lun2
zfs create -s -b 64K -V 750G rp1/iscsi/lun3
zfs create mp1/iscsi
zfs create -s -b 64K -V 750G mp1/iscsi/lun0

Originally I wanted to build the ESX hosts using a local disk but thanks to some bad IBM x346 engineering I could not use the QLA4050C and an integrated Adaptec controller on the ESX host server hardware. So I decided to give boot from iSCSI a go thus here is the boot LUN definition that I used for it. The original architectural design requires local disk to prevent an ESX host failure in the event of an iSCSI path outtage.

zfs create rp1/iscsi/boot
zfs create -s -V 16G rp1/iscsi/boot/esx1

Now that the ZFS stores are complete we can create the iSCSI targets for the ESX hosts to use. I have named the target alias to reflect something about the storage system which makes it easier to work with. I also created an iSCSI configuration store so we can persist the iSCSI targets on reboots. (This may now be included with Opensolaris Indiana but I have not tested it)

mkdir /etc/iscsi/config
iscsitadm modify admin –base-directory /etc/iscsi/config
iscsitadm create target -u 0 -b /dev/zvol/rdsk/rp1/iscsi/lun0 ss1-zrp1
iscsitadm create target -u 1 -b /dev/zvol/rdsk/rp1/iscsi/lun1 ss1-zrp1
iscsitadm create target -u 2 -b /dev/zvol/rdsk/rp1/iscsi/lun2 ss1-zrp1
iscsitadm create target -u 3 -b /dev/zvol/rdsk/rp1/iscsi/lun3 ss1-zrp1
iscsitadm create target -b /dev/zvol/rdsk/mp1/iscsi/lun0 ss1-zmp1
iscsitadm create target -b /dev/zvol/rdsk/rp1/iscsi/boot/esx1 ss1-esx1-boot

Most blog examples of enabling targets show the ZFS command line method as shareiscsi=on. This works well for a new iqn but if you want to allocate additional LUN under that iqn then you need to use this –b backing store method.

Now that we have some targets you should be able to list them using:

iscsitadm list target

Notice that we only see one iqn for ss1-zrp1, you can use the –v option to show all the LUN’s if required.

Target: ss1-zrp1
iSCSI Name: iqn.1986-03.com.sun:02:eb9c3683-9b2d-ccf4-8ae0-85c7432f3ef6.ss1-zrp1
Connections: 2
Target: ss1-zmp1
iSCSI Name: iqn.1986-03.com.sun:02:36fd5688-7521-42bc-b65e-9f777e8bfbe6.ss1-zmp1
Connections: 2
Target: ss1-esx1-boot
iSCSI Name: iqn.1986-03.com.sun:02:d1ecaed7-459a-e4b1-a875-b4d5df72de40.ss1-esx1-boot
Connections: 2

It would be prudent to create some target initiator entries to allow authorization control of what initiator iqn’s can connect to a particular target.
This is an important step. It will create the ability to use CHAP or at least only allow named iqn’s to connect to that target. iSNS also provides a similar service.

iscsitadm create initiator –iqn iqn.2000-04.com.qlogic:qla4050c.esx1.1 esx1.1
iscsitadm create initiator –iqn iqn.2000-04.com.qlogic:qla4050c.esx1.2 esx1.2

Now we can assign these initiators to a target and then the target will only accept those initiators. You can also add CHAP authentication as well, but that’s beyond the scope of this blog.

iscsitadm modify target –acl esx1.1 ss1-esx1-boot
iscsitadm modify target –acl esx1.2 ss1-esx1-boot
iscsitadm modify target –acl esx1.1 ss1-zrp1
iscsitadm modify target –acl esx1.2 ss1-zrp1
iscsitadm modify target –acl esx1.1 ss1-zmp1
iscsitadm modify target –acl esx1.2 ss1-zmp1

In order to boot from the target LUN we need to configure the QLA4050C boot feature. You must do this from the ESX host using the ctrl Q sequence during the boot cycle. It is simply a matter of entering the primary boot target IP set the mode to manual and enter the iqn exactly as it was listed from the iscsitadm list targets command. e.g.

iqn.1986-03.com.sun:02:d1ecaed7-459a-e4b1-a875-b4d5df72de40.ss1-esx1-boot

Once the iqn is entered the ESX host software can be installed and configured.
Till next time….

Site Contents: © 2008  Mike La Spina