Non Destructive hard disk write benchmark for a server

wasc · 18 Sep 2009 at 18:43

Hi,

I have a Dell server with an external MD1000 DAS unit attached running Raid 6.

I'm a little worried the server may be underperforming as it seems sluggish accessing the external disks. Therefore I'd like to run some benchmarks to get some figures of what the unit can do.

A google search found lots of benchmark tools, but to do a write test they all seem to want to wipe your disks - i.e. they are destructive. The only other one I found simply copies a file from one place to another so is testing the performance of other parts of the server and not necessarily the external drive.

Idealy what I want is a program which generates a large file, and saves it to the external drive and measures the MB/sec. Then generates maybe 100 smaller files and measures that speed too.

Does such a tool exist? Preferably free

Ringiho · 18 Sep 2009 at 18:46

Depends how awesome you want it to be an what OS

For linux, something like IOMeter can be pretty awesome. Otherwise you can try simple stuff like HDTune etc for Windows. I have done some basic testing with these to see how poor/good an array was. Nothing to rely on though

wasc · 18 Sep 2009 at 18:52

Ringiho said:
Depends how awesome you want it to be an what OS

For linux, something like IOMeter can be pretty awesome. Otherwise you can try simple stuff like HDTune etc for Windows. I have done some basic testing with these to see how poor/good an array was. Nothing to rely on though

Ah yes, forgot to mention the OS.

It's Windows 2008 64bit. I'm pretty sure I've used HD Tune before but to do a write test it wipes the disks - I'll double check though as I may be wrong.

I've already tested the read performance and it's fast enough - I'm just worried the write might be slow with the two sets of parity to calculate for the raid 6.

Ringiho · 18 Sep 2009 at 18:55

What sort of speeds are you getting? How many disks are the RAID6's running?

Saundie · 18 Sep 2009 at 19:12

ATTO Disk Benchmark can test writes, and while it's getting on a bit now it may still prove useful to you - at least to get a rough idea as to the write performance of the array.

Yamahahahahaha · 18 Sep 2009 at 20:21

The MD1000 isn't as fast as one might expect.
Something like 350MB/s sustained read / write fully laden with 400GB SAS drives in RAID6.

Nothing to be sniffed at, and nice for databases (SPINDLES!)

Ringiho · 19 Sep 2009 at 14:57

Yamahahahahaha said:
The MD1000 isn't as fast as one might expect.
Something like 350MB/s sustained read / write fully laden with 400GB SAS drives in RAID6.

Nothing to be sniffed at, and nice for databases (SPINDLES!)

SAS could be faster though! You can get around 300MB/s from a RAID10 of 4 SAS disks. How many disks does it take?

Saundie · 19 Sep 2009 at 16:35

Ringiho said:
SAS could be faster though! You can get around 300MB/s from a RAID10 of 4 SAS disks. How many disks does it take?

It takes up to 15 disks. I had one with six 500GB 7200RPM drives in RAID5, it was able to push around the same figures Yamahahahahaha mentioned. I'm not sure if I kept the benchmark results, I'll have a look for them.

Yamahahahahaha · 19 Sep 2009 at 17:45

It just occured to me that the test system I was using it on was connected with SCSI 320. That would explain the results. *Facepalm*

These days you should be looking at iSCSI SAN with 10gbit+ to the core if you want fast storage.

Ringiho · 19 Sep 2009 at 22:40

Even ISCSI at 1GB would be pretty awesome. Or Fibre Channel

wasc · 21 Sep 2009 at 14:03

Thanks for the replies - I'll test ATTO out.

To answer some of the questions, the server has 8 x 1TB Nearline SAS drives in it as Raid 6. (So a 6Tb volume).

I know the nearline sas drives are basically sata drives with a sas controller chip on before someone points it out.

Ringiho · 21 Sep 2009 at 18:55

ATTO is a good benchmark really! Couldnt remember the name though