EqualLogic - SAS or SATA?

[chris_delaney]

Hello Everybody,

I'm involved in a SAN procurement and we have pretty much decided that EqualLogic is the way to go. Does anyone know of any performance stats where the SAS and SATA appliances are compared with EMC/NetApp etc?

Failing that, does anyone have any experience with SATA EqualLogic appliances and their performance with VI3?

Many thanks.

Chris

[AnthonyM]

Hi Chris,

http://www.vmware.com/community/message.jspa?messageID=644214#644214 may be a good start.

I have just got the PS100E installed, and am very happy with it.

Regards

Anthony

[admin]

We trailed a PS50E SATA based Equallogic, and were imperssed by how fast it was, especially as the bottom of the range unit. There's no getting away from the fact however that SCSI disks will be faster than SATA for non-sequential random I/O use - it's just not the sort of work SATA was designed for.

That's not to say the performance isn't acceptable with SATA, it depends what you're doing with it, but IMO the SCSI drives will always be faster (currently), but then they're more expensive too!

[chris_delaney]

Interesting. We're not a very big setup but looking at their claims I think we should be OK with the SATA boxes for production VMs.

Many thanks guys.

[woharrow · Accepted solution]

I have seen many customers on the SATA class PS arrays working fine. The question is how many VI3 Servers and How many VMs.

One comes to mind where they are running a 4 member PS Array group with 4 ESX VI3 servers holding 125 VMs with no issues at all. This 4 member group is also serving space to 12+ other servers running large SQL databases, etc... Another one is a customer running 70+ VMs on 8 Hosts with 2 PS-300Es.

As for SATA vs. SCSI at the disk level, I would agree if you are looking at a single drive. However, when you are looking at a SAN there are so many other components playing a critial part in the I/O path that the disk takes a much more minor roll. The number of disks and Disk Bus Paths is critical to the equation.

The more import thing will be how you set the environment up, since you need to make sure things are threaded properly to give you the best performance.

Hope this answers your question.

Wade

[Dus10]

Guys, you really have to think about how these Equallogic SANs are setup. You really shouldn't be hung up on SAS v. SATA. Each array is setup with 14 disks. Typically, you are going to have a RAID 50 setup with two spares. So you have two arrays setup with RAID 5 with six disks each. Then, you stripe those two arrays. You could probably get bet with IDE (okay, I am exaggerating a bit). Anyhow, beyond that, they are optimized and have a 2GB battery backed cache.

Also, unlike most other SANs, the Equallogic's performance improves as you add arrays because it optimizes the location of data by how often it is accessed.

These things aren't the most expensive, but that really doesn't matter. Their support is excellent. You will be fine with a PS100E. If you need more disk space, add a second array and you will also get extra performance.

[christianZ]

That's my estimation (not committal) -

FAS270 < 1 x PS100 < FAS3020 ~ 1 x PS3600

2 x PS3600 ~ FAS3050

all this with comparable disks count and NetApp over FC (NetApp over iSCSI should be slower).

Don't forget the features costs(snapshots, snapshots r/w, volume copy, volume restore from snap, replication...) - by EQL all inclusive (new FW 3.2 this quarter with thin provisioning and better replication).

Just my 2 cents.

[chris_delaney]

Many thanks again everybody. We have EqualLogic coming in today to speak to us so your comments have reassured me in advance. Be nice to get the VMs off local storage at last!