topic Re: Disk Size to Performance in Disk Enclosures

Disk Size to Performance

Sajeev2007 — Thu, 24 Jan 2008 17:46:32 GMT

Does the Virtual disk size affect performance ?

For Eg: do you recommend creating one large 2TB LUN or multiple smaller LUNs to be assigned to one server.

Thanks,

Sajeev

Re: Disk Size to Performance

Ivan Ferreira — Thu, 24 Jan 2008 18:14:57 GMT

In case of Virtual Disks, from the storage perspective, the LUN size does not affects the performance.

But you could get performance benefits from the operating system perspective, if you have more than one LUN, as cache/queues are asignes in a per LUN basis.

If where up to me, I would create 500 GB LUNs.

You should also consider your backup strategy.

If you can, try to put read-only information in a separate LUN, so you can backup this less frequently.

Re: Disk Size to Performance

Hasan Atasoy — Thu, 24 Jan 2008 18:19:19 GMT

hi;

I would recommend smaller size luns ( around 500Gb for your conf ) , because luns will be distributed among controller, more easy administration task, more easy backup administration, queu depth settings and more.

Hasan.

Re: Disk Size to Performance

Sajeev2007 — Thu, 24 Jan 2008 18:34:31 GMT

what if its a VM Ware cluster with 6 TB and 6 ESX servers

Re: Disk Size to Performance

Michael Steele_2 — Thu, 24 Jan 2008 19:02:01 GMT

Hi Sajeev:

The more the better. The bigger the fire hose the faster the water is delivered. Here are some areas that you can control to get faster delivery.

File system block size. Bigger blocks mean less work for the transfer.

Stripping across spindles and disks. The more spindles the less work to perform when read / writting.

HBA's. Get as many as possible on both server and disk array and round robin the HBA
s (* pri > alt alt > pri *) to balance evenly across the HBA's.

Raid 1 is faster than Raid 5. Put your database on raid 5 and your archive logs on raid 1.

Use one disk group in the disk array. Especially if you're limited by only two HBA controllers.