I seen this situation once before when the "parity is unsynced" corruption
can be caused in the filesystems on the ssa array. And cause the data to
become unrecoverable. I saw this happen on an AIX 4.2.1 system before IBM
told me that there was nothing that could be done to recover the data and we
would have to recover from backup.
-----Original Message-----
From: Cook, Dwight E [mailto:[EMAIL PROTECTED]]
Sent: Monday, April 23, 2001 10:27 AM
To: [EMAIL PROTECTED]
Subject: Re: RAID-5 Vs Mirroring
Were you using just a single card ?
Have you ever played with "higher availability" SSA card configurations ?
Take two cards and set up something like
Card1-PortA1 -> out to drawer(s)
Card1-PortA2 <-> Card2-PortA1
Card2-PortA2 -> out to drawer(s)
then if either card fails, the other still drives the environment.
you can do the same with the B-Loop
Dwight
-----Original Message-----
From: Andy Carlson [mailto:[EMAIL PROTECTED]]
Sent: Monday, April 23, 2001 9:03 AM
To: [EMAIL PROTECTED]
Subject: Re: RAID-5 Vs Mirroring
One comment about the raid - we got away from SSA hardware raid after we
had two SSA card failures that caused the loss of the database. If I
were forced to use raid, I would have the second copy, and put the raids
on separate SSA cards.
Andy Carlson |\ _,,,---,,_
[EMAIL PROTECTED] ZZZzz /,`.-'`' -. ;-;;,_
BJC Health System |,4- ) )-,_. ,\ ( `'-'
St. Louis, Missouri '---''(_/--' `-'\_)
Cat Pics: http://andyc.dyndns.org/animal.html
On Sun, 22 Apr 2001, Mahesh Babbar wrote:
> Hi all,
>
> Environment:
>
> NSM 3466, RS 6000, AIX 4.3.2 , TSM version 3.7.4,
>
> 12 x 18.2 GB disk ( for DB and Diskpool Volumes)
>
> My current DB is of 80 GB size and is alarmingly utililized ( 95
> %).The DB volulmes are mirrored inside TSM ( Second Copy).
>
> Therefore another 80 GB space is being used for the second copies. In
> order to have more usable space for DB, a suggestion has been mooted
> to go for RAID-5 at the hardware level.
>
> IBM's version is that since a second copy MUST be kept , going for
> RAID 5 shall require more disk space. Now my question is:
>
> 1. With the RAID 5 at AIX level, should a second, synchronized copy
> of DB volumes is required.
>
> 2. If I do not keep a second copy and take daily full backup, would
it
> be RISKY.
>
> 3. Configuring RAID 5 at this juncture, would anybody see any pitfall
> ahead.
>
> Any comments are welcome!
>
> Regards
>
> MAhesh
>
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