SQL Server Performance

SQL Server Deployment Disk Set-up

Discussion in 'Performance Tuning for DBAs' started by seasider, Mar 11, 2003.

  1. seasider New Member

    I am in the process of re-evaluating our standard system deployment guide. Currently we deploy our systems onto a SQL2K cluster + SAN with this config:

    DB Data - RAID 1 (varying number of 36GB disks)
    DB Logs - RAID 1 (varying numer of 36GB disks)
    DB Backups - RAID 5 (varying numer of 72GB disks)
    File Store (App templates, Windows user profiles etc...) - RAID 5

    This is for systems of up to 500 concurrent users with a database size of up to 100GB and a Read:Write ratio of around 1:9.

    Surprisingly I do not like the look of this!

    I am thinking more along the lines of this:

    DB Data - RAID 10 (or RAID 5 where cost is an issue)
    DB Logs - RAID 1
    DB Backups - RAID 1
    File Store - RAID 1

    What do you reckon? My main area of concern is the file storage (backups, templates, user profiles etc...). These will be kept seperate from the DB files but would RAID 1 be the best choice for these files?

    Would RAID 1 help with the performance of backups, I presume that the current approach of RAID 5 will slow it down.

    We would be backing DB backups off to tape regularily (every night). The file store would be backed up perhaps once per week.
  2. dtipton New Member

    Given the ratio:

    "Read:Write ratio of around 1:9"

    one read for every nine writes

    Wy would you consider a move from RAID1 to RAID5 for database files?

    I was under the impression that RAID 5 offered increased read performance, but decreased write performance(parity calculation).
  3. seasider New Member

    Sorry, it a typo!

    It is actually 9 Reads to every 1 Write.

    Apologies.
  4. sqljunkie New Member

    I normally only recommend Raid-10, but in your case with that 9:1 ratio you could get by with Raid-5 where cost is an issue
  5. bradmcgehee New Member

    I agree with your new recommendation, plus what rortloff says. In most cases RAID 5 won't be much slower than RAID 10 given you read to write ratio, but if you have the money to spend, spend it on RAID 10. There is no such thing as being too fast.

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    Brad M. McGehee
    Webmaster
    SQL-Server-Performance.Com

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