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
Here is a good presentation about vmwares DVS technology. Essentially a new way to create a vSwitch over a cluster and just add the required hosts into it.
http://download3.vmware.com/vdcos/demos/DVS_Demo_800×600.html
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…
First format your usb / flash drive with FAT. Then copy all the contents of the installer .iso onto the drive.
Next delete isolinux.bin and rename isolinux.cfg to syslinux.cfg
Edit syslinux.cfg and append “usb” to the line starting with “append” … i.e. similar to this
append vmkboot.gz — vmkernel.gz — sys.vgz — cim.vgz — ienviron.tgz — image.tgz — install.tgz usb
Next grab the latest syslinux.exe (zip for windows) from here and run syslinux -s –ma <driveletter>:
Done.
Its quite easy to boot esx from a usb device or flash card..
First download the .iso, then browse with winrar or similar. See if you can find the “big”.dd file this is the file we need.
i.e. the ESXi 4 file is called VMware-VMvisor-big-208167-x86_64.dd
Next grab WinImage and “restore image to physical harddrive” choose the .dd file the select your usb / flash drive.
Done.