June 23, 2003 at 7:03 pm
Hi All,
I have got the approval (after long fight) for expanding storage in our Server(SQL2K). Right now we are having 4 DISKS (36GB Each) with RAID-5 (including 1 for Parity).
I am planning to add another 2 Drive Cage with 72GB each with RAID-1 Mirroring.
Can any one please tell me what would be the best approach?! Moving the Database Files to RAID-1? Moving Logs to RAID-1? Moving Both DATA and LOGS to RAID-1?
Is there a recommended location for Backups (both Database as well Transaction Log Backups)? We are taking differential backup everyday as well as Weekly backup on Monday to Tape.
Your thoughts are much appreciated.
Regards,
mdamera.
.
June 23, 2003 at 9:19 pm
Hi
Im a little confused with the total # disks, can you tell us this number and their size, ie. 5 disks @ 36Gb etc. Can you also mention how you connect to the disk array.
Generally, I do this:
a) RAID-5, indexes and/or data
b) RAID-1, audit and/or data
c) RAID-1, logs
I stuff my sys databases on a single raid-1 array.
The "main" app, that has file groups for DATA, INDEX, AUDIT, I have 2xraid-1 and a 1xraid-5 array, scsi 320 with 40Mb cache, 15k drives. I have a lot of users with a mix of oltp and dss and the dispersement below works very well for me..
raid-5 FG_DATA, FG_INDEX
raid-1 FG_LOG
raid-1 FG_AUDIT, <backups>
with many db's that are large, it can be tough going with the dispersement of files around the array. Concentrate on reducing IO via a well tuned app and the disks become less of a headache (sometimes!).
Cheers
Ck
Chris Kempster
Author of "SQL Server 2k for the Oracle DBA"
Chris Kempster
www.chriskempster.com
Author of "SQL Server Backup, Recovery & Troubleshooting"
Author of "SQL Server 2k for the Oracle DBA"
June 23, 2003 at 9:35 pm
I apologize for the confusion.
Right now I have 4 disks @ 36GB as RAID-5 array. This is devided into C, D Drive letters. 4GB for C and the rest for D.
I am going to add 2 disks @ 72 GB each as RAID-1 array.
I do not have any file groups other than Primary.
Thanks Again.
.
June 28, 2003 at 11:16 am
Any Thought?????
.
June 28, 2003 at 12:36 pm
mdamera,
First of all, you must take RAM into the equation as your OS will be doing a lot of swapping to disk if you do not have enough RAM. Next piece is try to seperate the logical containers on physical channels. What I mean is you do not want your reads and you writes on the same scsi channels. There is only so much bandwidth on those channels and they get consumed by doing both functions.
Config you should follow is as follows:
CHANNEL0, RAID 1, TWO CONTAINERS C: D: Put OS/SQL on C:, TLOGS on D: This allows you to blast your OS/SQL install if you ever need to without impacting the Database.
You want to use RAID 1, because these containers will be doing heavy writing (read tlogs.) It is best to do writes across fewer drives and reads across many.
CHANNEL1, RAID 5, 1 CONTAINER E: Put your actualy DB on this container and use all 4 drives. A fifth would be nice to have a hot spare feeding all containers, but not necessary (and not always configureable depending on your server type.)
Optimum config would be C/D/E drives all on seperate channels. That would unfortunately require at least 7 drives. Prefereably 10 to do it right. And it would require 2 raid cards (in most cases.)
Hope this helps.
-DoLo
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