SATA RAID annoyances

[Mike-Bracknell]

Regularly, since I work with SMEs, I virtualise entry-level servers (as a matter of course for VM portability, easy DR, etc).

In some occasions I find that the hardware vendor has been cheap with their choice of RAID card, providing one that will either not do RAID5 or won't allow you to create RAID partitions on disk subsystems.

This causes a problem with VMware as it's disk usage requirements for install are a bit like Goldilocks - you can't have a disk too small, and you can't have a disk too large, and if you go over either of these boundaries you get VMware either not installing, or installing a default datastore which is a fraction of the size of the underlying disk (like the 1.47Tb datastore in my current 5.47Tb system).

Hence, since I can't do much about VMware, I can do something about the RAID card.

So, what i'm looking for are suggestions for PCI-express SATA RAID cards that provide RAID0/1/5 and the ability to RAID disk partitions rather than the complete disk.....oh and they can't cost more than say £200.

Any ideas?

[Saab Dastard]

I assume you have checked the VMware HCL (http://www.vmware.com/resources/compatibility/search.php) and you are installing ESXi 4.1 standalone ('cos it's free!)?

Something like the Adaptec 5405 (http://www.adaptec.com/en-us/support/raid/sas_raid/sas-5405/) or 3405 (http://www.adaptec.com/en-us/products/controllers/hardware/sas/value/sas-3405/) tick most boxes and are not far above your price ceiling - and they are on the VMware HCL.

Not used them myself, but I've never been disappointed with Adaptec kit.

SD

[Mike-Bracknell]

The HCL is a lot less critical these days, as most kit is supported in one way or another now.

I use both ESX and ESXi, and mainly not free as i'm also a Veeam silver reseller and you can't back up the free ESXi hypervisor due to VMware enforcing that a couple of years ago.

However, neither hypervisor is too different from the other now and both have the restriction on the initial datastore.

I've had good experiences with Adaptec kit in the past, but was just trying to see whether there were competing cheaper options, as Adaptec has always been a bit pricey in comparison.

[Saab Dastard]

This causes a problem with VMware as it's disk usage requirements for install are a bit like Goldilocks - you can't have a disk too small, and you can't have a disk too large, and if you go over either of these boundaries you get VMware either not installing, or installing a default datastore which is a fraction of the size of the underlying disk (like the 1.47Tb datastore in my current 5.47Tb system).

You do know that ESX/ESXi VMFS3 has a maximum usable disk size of 2TB?

You should aim to create your logical RAID disks less than this value. RAID5 is a problem with large disks. Better to create several RAID1 disks.

You can create a VMFS3 volume up to 64TB by adding extents.

SD

[Mike-Bracknell]

Yes I know that. However the issue surrounds the primary datastore. I can create datastores and extents to my hearts content once I have a primary datastore, but the install process doesn't allow you to select a sector size for the format, so even a 1.47Tb primary datastore in this example is useless when it won't allow snapshotting of disks larger than ~200Gb. All I want is the ability to partition approx 20-50Gb for a primary datastore (to contain ISOs etc) and leave me with the rest of the disks to configure how I need.

[mixture]

Mike,

You do realise the cheaper RAID cards are hardly worth the effort as they are software RAID implementations and so you are gaining none of the benefits of installing a RAID card (including performance which is lousy on the cheap cards).

I would suggest sticking with Adaptec, LSI or any of the other larger brands rather than going for something lesser known just because "it's cheaper".

After all, dodgy RAID will do nothing but test your insurance policies. :cool:

[Mike-Bracknell]

I'm (or rather the person who writes LSI's webBIOS is) an idiot.

The whole point of this thread was because I was battling with an LSI MegaRAID card on this Lenovo Thinkserver TD200.

I've now spent a lot more time on it, and found the functionality I originally thought was missing! What you'd think you need to create virtual drives of a specific size, is actually completed by running forwards and backwards in the WebBIOS screens using something called "Span Holes", creating drives of a specific size (which originally refused to allow me to type the drive size).

I'm now a happy bunny, and can confirm the LSI cheap SATA RAID cards now DO do what you want them to. :ok: