SATA in an XP24K

[Nigel Poulton]

Hi all,

Has anybody installed SATA disks internal in an XP24000/USP V?

If so are you aware of any best practices when it comes to CLPR config and backend looping etc?

Many thanks.

[Torsten.]

It's possible according to this:

http://h18000.www1.hp.com/products/quickspecs/12711_na/12711_na.html

[Nigel Poulton]

Thanks Thorsten,

I should have been more clear. I know that it is supported. But I also know that Hitachi were very reluctant to support SATA internally in the XP and only gave in due to competitor pressure and the likes.

So Im not happy just isntalling them without hearing some experiences from others and hopefully some best practice advice re CLPR confgs etc.....

Thanks again

[IBaltay]

Hi,
there is some info in the quickspecs on the SATA drives:
http://h18006.www1.hp.com/products/quickspecs/12711_div/12711_div.html

due to the SATA drives performance it is a good idea to partition them to the separate CLPR...

[Amar_Joshi]

Nigel,

SATA drives are slower (unpredictably slower) than FC drives. If the write-chache is shared between FC and SATA drives then it may so happen that SATA will fill it because of it's slow performance hence it's highly recommended to use a separate CLPR for SATA drives. It's the same logic used for External storages where connection problems can impact the cache for internal drives hence also recommended to be kept in difference CLPR.

Not sure what do you mean by backend looping? Backend architecture is fixed for FC/SATA drives and can't be tuned for any such configuration.

[Nigel Poulton]

Amardeep,

What I mean by backend looping is whether or not there is a best practice for a max number of SATA spindles per loop etc so that they dont impact FC disks....

While its not "quite" the same, you have to be very careful when installing SSD so that they do not starve normal rotating media of internal resources......(back end loop layout being of critical importance). Im wanting to take similar care with SATA as I know that Hitachi were very much against supporting SATA in an otherwise tier 1 array, and they had reasons to be against the idea.

I know that for their midrange storage Hitachi imposed a verify after write operation on every write to SATA which really slowed the array down. I am assuming that this behaviour is not imposed on the USPV/XP.

Lots of people with theoretical ideas, and thank you for your ideas. However, Im quite well versed in XPs and was hoping some of you might be able to quote from experience. It seems like nobody on here has done this yet.

Thanks,

Nigel

[IBaltay]

some other notes:
a) not 4 mission critical apps where the performance is important
b) both BC/CA PVOLs/SVOLs should be SATA
c) not for the CA journal vols for the CA journal
d) should be placed in the ThP (SATA pool only)
e) only 6D+2P

[Nigel Poulton]

The result of some digging and applied theory leading to the following unofficial best practices -

http://blogs.rupturedmonkey.com/?p=404

Hopefully wil help people who want to deploy SATA in an XP in the future.

Nigel