From: Billy Tyrer (wtyrer@CSC.COM)
Date: Wed Nov 27 2002 - 11:21:15 EST
Wesley, perhaps the information below will be of some use to you,
especially if you are configuring F/W CACHE
within an HACMP cluster!!
The command below will display the fast/write cache for a ssa adapter.
This commands will also show you at what level of microcode level the
adapter is running and indeed
what model of adapter is being used.
ssaraid -I -l ssa0|grep fastwrite|uniq
"lscfg -vl ssa0" you should see a line like this :
Device Specific.(Z1)........CACHE=32
The CACHE=32 indicates that the ssa adapter does have fast write cache
installed . If you are using RAID 5 this should not be installed as it is
slow on writes.
SSA CACHE is not supported in hacmp because during failover you would lose
the data in the cache.
Billy.
Wesley Joyce
<Wesley.Joyce To: aix-l@Princeton.EDU
@UVI.EDU> cc:
Sent by: IBM Subject: Re: How many SSA disks to configure in a RAID array ?
AIX
Discussion
List <aix-l
27/11/02
14:46
Please
respond to
IBM AIX
Discussion
List
Okay. I would like to elaborate on the setup.
It will be two 650s each with 7133s w/ 6 18GB SSA. HACMP will be setup. I
have a concern that if I mirror to much within on node/drawer that I will
drastically reduce my file storage and PVs that can be added to VGs. Can
the mirroring be done across the HACMP nodes and their respective
drawers/disks so in essence I have 108GB of RAID 1 within the cluster?
At 10:34 AM 11/27/2002, you wrote:
>These days, with fast disk drives, big disk capacities and write-caching
>controllers, RAID level is less of a factor than it used to be. As I
>understand it, a more critical aspect to DB performance is separation of
>workload; i.e., isolating disk I/O for data files vs indexes vs redo
>logs. You also have to weigh cost, as well, and you need to consider
>how much SSA bandwidth you have and gauge your opportunities for future
>growth. If you choose RAID-5, you'd be best served to have fast-write
>cache on your SSA card.
>
>Regards,
>
>James Jackson
>
>-----Original Message-----
>From: Wesley Joyce [mailto:Wesley.Joyce@UVI.EDU]
>Sent: Wednesday, November 27, 2002 8:01 AM
>To: aix-l@Princeton.EDU
>Subject: Re: How many SSA disks to configure in a RAID array ?
>
>
>I would like to add a related question. I am obtaining a 7133 with 6
>18GB
>drives. I remember when it was best to setup a different RAID level
>based
>on the type of files that would be stored. Is this still recommend or
>can
>I go with a RAID 5? Data that will be stored will be Oracle data,
>Content
>Manager and user home directories.
>
>At 04:09 AM 11/27/2002, you wrote:
>
> >Hi sachin
> >
> >In case you have a single SSA controller , I suppose you would be
>better off
> >putting all your disk in one raid , so you can stripe across five disks
> >instead of 3 or 2 as the case maybe.
> >
> >Regards
> >Shirish joshi
> >
> >
> > -----Original Message-----
> >From: Ganu Sachin, IBM [mailto:Sachin.Ganu@KWA2.SIEMENS.CO.IN]
> >Sent: 27 November 2002 10:41
> >To: aix-l@Princeton.EDU
> >Subject: How many SSA disks to configure in a RAID array ?
> >
> >Hi
> >
> >I am going to install 5 x 72 GB SSA disks (10K RPM) in RAID 0
>configuration
> >in a 7133 box. I have a SSA controller with onboard 128 MB SDRAM & 32
>MB
> >FastWrite cache. Do I configure 1st RAID 0 set with 3 disks in loop A
>and
> >2nd RAID 0 set with 2 disks in loop B or do I configure these 5 SSA
>disks in
> >single RAID 0 array on loop A ? I am not bothered redundancy / fault
> >tolerance.
> >
> >Your expert comments please ....
> >
> >Thanks & regards
> >
> >Sachin Ganu
> >IBM Global Services
> >
> >
> >
> >
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>
>Wesley Joyce, Systems Administrator
>Center for Administrative Computing (CAC), IT
>University of the Virgin Islands
>#2 John Brewers Bay, St. Thomas, USVI 00802-9990
>(340) 693-1469 (voice) / (340) 693-1465 (fax)
>http://www.uvi.edu
>
>"If you can't explain it simply, than you don't know it well enough. -
>Unknown."
>
>
>
>
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