Continuing on from this http://sigtar.com/2010/02/04/vsphere-and-multipathing-iscsi/
you may want to implement jumbo frames to your iSCSI backend…
Enable jumbo frames on your iSCSI target and switches then complete the following on the ESXi hosts (iSCSI initiators)…
This to list your current switch details and port group names…
esxcfg-vswitch -l
The follownig to allow jumbo frames onto your vswtich (insert your vSwich in following)
esxcfg-vswtich -m 9000 vSwitch0
Then delete and recreate your kernel port groups that you setup for iscsi, my commands looked like this… (repeat for each iscsi kernel port you have)
esxcfg-vmknic -d iSCSI-1
esxcfg-vmknic -i 10.0.0.101 -n 255.255.0.0 -m 9000 iSCSI-1
to confirm you have set the MTU (frame size) correctely, run the following….
esxcfg-vmknic -l
you should see your iSCSI kernel ports with a MTU of 9000 all going well.
This is just a quick reference to create a multiplathing iSCSI setup…
Create two virtual kernel switches, one called “iSCSI-1″ and the other called “iSCSI-2″ (and so on if you have more nics)
Then per kernel portgroup ensure that only one of the nics is active. For the “iSCSI-1″ portgroup configure it to override the virtual switch settings and move nic 0 to active and nic 1 to unused. For the “iSCSI-2″ portgroup configure it to override the virtual switch settings and move nic 1 to active and nic 0 to unused.
Now you have to run some esxcli commands to gel things together…. alt-f1 on the esxi console and type “unsupported” followed by your root password. The following is the command i have to run to get both my portgroups to work together on the iscsi hba…. (you can check your vmk number from the networking config screen)
esxcli swiscsi nic add -n vmk1 -d vmhba33
esxcli swiscsi nic add -n vmk2 -d vmhba33
For each target then change the path selection method to “round-robin”.
Go back to storage adapters and click “rescan”
If you want all future iSCSI targets to automatically use round-robin you must also run the following from commandline… (this is for our HP Lefthand, your “storage array type” may be different. Its listed under your target details). Basically sets round robin as a default for this type of array. In general you should do this first before presenting any LUNs etc, else you may have to bounce your box.
esxcli nmp satp setdefaultpsp –satp VMW_SATP_DEFAULT_AA –psp VMW_PSP_RR
I’ve got some old 250Gb drives that are starting to show their age. I’ve currently got them setup in a 3x RAID 0 config which presents about 750Gb of space.
I’ve got everything on a single partition (meh, i’m lazy). I’ve done various speed tests in the current setup (with all space allocated), but i thought i’d re-image onto a short stroke partition.
I only use about 150Gb of space on my main machine (most of my data is on another box), so i’m going to try creating a 200Gb partition to test if this provides any kind of performance boost.
So reducing my raid 0 from 750Gb to 214Gb, and here are the results…
Before with all 750Gb presented…
Same disks but short stroked to 214Gb….
Conclusion : Yip, seems like its worth it if you have the spare space. Average throughput is up by 10MB/s and seek has improved by almost a third loosing 4ms.
You will get even more of an improvement if you can use a smaller % of capacity per drive and / or more drives for your stripe.
Updated : 07/02/2010
btw – the above was without write-back cache enabled…. if i turned that on i got the following…
Want iSCSI in opensolaris?
Grab SUNWiscsitgt via package manager.
enable the server via svcadm;
svcadm enable iscsitgt
create your zfs iscsi pool; (this command will limit iscsi drive to 500GB in size)
zfs create -V 500G tank/iscsi
set isci on via zfs command;
zfs set shareiscsi=on tank/iscsi
check that target is up and running;
iscsitadm list target -v
Done. Should be able to connect via ip from another machine. I have not covered CHAP or any client side configuration. Assumed isolated LAN.
If you want to give zfs a go and also want a dedicated file server this is the solution.
Check it out here;
http://www.freenas.org/
I’m still using opensolaris though as i like running a few virtualbox machines on the same box.