SAS and SATA datastores on same box?

[evandena]

I'm looking at a potential ESX box, and I'm wondering if the following hypothetical situation is possible.

I have a Dell Perc 5/i RAID controller with 2 arrays, 2xSAS and 4xSATA.

I would like to have ESX and the VM's operating systems reside on the faster SAS disk and then simply attach virtual drives to the VM's from the SATA array.

So I guess the question boils down to, is it possible to have two datastores from a single host, both being local disk?

Thanks

[weinstein5]

As long as the hardware is supported - I do not see why it should not work - just remember being local no vmotion/drs/ha

[evandena]

Thanks for the insight weinstein5. If you think it will work, I'll start to move forward with the build.

I still wouldn't mind a definate answer though to ease my mind. :smileyblush:

[dmaster]

Hello Evandena,

Be aware that most SATA controllers are not compatible with esx for hosting vm's. Probably you can use them for the esx build itselve but you get problems when you create a vmfs volume or a vmkernel parttion.

This trick only works for some rare raid sata controllers.. but all scenario's it is unsupported by VMware. SCSI disks are the only supported local storage devices for hosting vm's.

However you could put the SATA disks in another light dedicated desktop/server and create a iSCSI target out of it..but be sure to use a gigabit connection between the esx host and the iscsi target. There are a lot of virtual iSCSI appliances available nowadays.. for example www.openfiler.com

[evandena]

Thanks dmaster.

I tried openfiler and NFS, but without an expensive RAID card the performance was very poor.

So even though the Perc 5/i is a supported SAS controller, it will not work with SATA disks? The card supports SATA through a cable such as this

Support from VMware is not necessary, as this is strictly an personal test box.

[weinstein5]

openfiler will hide the disks technology - so as long openfiler sees the SATA/SAS drives and can present them as iSCSI targets the ESX hoists should see them with no problems - what the others are talking to is when you install SAS/SATA controllers in your ESX host -

[evandena]

Sorry for the confusion, but I would like use the ESX host and have nothing to do with Openfiler. What I was saying is that I've used it before and without building two powerful boxes, I did not get the profmrance I was looking for.

So yes, I would like to use SAS and SATA on the same host.

[dmaster]

Hello Evandena,

now i see what you mean.. you use a SCSI to SATA converter this changes the story..

i have a collegue who did the same as you mentioned.. and yes it worked perfectly for him..

only drawback with SATA drive is that the performance will dramatically decrease when performing multiple actions on a SATA disk..

But you quickly know how many workloads you can store on the SATA array.

[evandena]

Thank you dmaster, I'm glad to hear that it will work.

Do you know if you collegue saw two datastores, one for SAS and one for SATA? You could even take the disk types out of the question and ask, will two arrays show as two data stores?

[dmaster · Accepted solution]

You will see it like this (two disk arrays).. in the VI-Client see screenshot. You can decide to make a hole datastore out of it or just use a partition on this disk..

this only works when you manually create a partition on this disk with partition type fb

[evandena]

Thanks!

Time to start ordering parts.