SQL Server Performance

Best configuration for 8 drive server?

Discussion in 'Performance Tuning for Hardware Configurations' started by csuttman, Jun 15, 2006.

  1. csuttman New Member

    My database server has 8 bays in it. Current configuration is 5 x 72GB 15k drives as Raid 5 and 2 x 34GB 10k drives as raid 1. 1 bay has a hot spare. The database is 40GB and growing fairly quickly. It has very high IO due to batch jobs that run steadily throughout the day inserting and updating records. There is also a steady heavy load of large, multi table selects. The database is in the Raid 5 array and the logs are on the Raid 1 array.

    When I watch perfmon during batch jobs... both arrays are working very hard and the server is crippled until the job finishes. We've already optimized the sql to the point where the time invested doesn't seem to be worth the gains any more.

    I've been told to reconfigure the drives to make a 4 x 72GB 15k Raid 10 array for the database and a 4 x 34GB 10k Raid 10 array for the logs. I know Raid 5 is supposed to be slow for database access, but can 4 disks as Raid 10 (where striping is only between 2 drives) really be faster than a 5 disk raid 5?

    One more consideration is that the server has 2 SCSI drive bays in it (which I believe each can take one channel) and I believe the raid controller is dual channel, but am not sure. If I really do have the ability to set up 2 completely seperate arrays on their own channels... how much difference does this really make in IO performance?

    I'm willing to buy some more hardware if the performance increase would be worth it. Otherwise I may be shopping for a new server, which isn't exactly a cheap fix. Any suggestions would be helpful.




    Louder+Harder+Faster >= Better
  2. joechang New Member

    the best config for a db server is to have 32+ disk drives spread across 8 u320 scsi channels or comparable SAS setup, plus 1-2 channels for the logs and other stuff

    this means use the internal bays as well as external storage units
  3. csuttman New Member

    I know I've heard the more spindles, the better. But how should they be configured is the question. Since 32 drives divided by 8 channels is 4 drives per channel, does that mean 4-drive Raid 1+0 is the fastest and most secure way to go?

    So in theory, I assume I should be dividing the database into multiple files so it can be split over the 8 channels (in an ideal world), right?

    Louder+Harder+Faster >= Better
  4. humut New Member

    Hi
    If i only had 8 drives i would 6 for data and 2 for log, i suggest you get rid of the 2 10k drives and replace them with 15k.
    Since your batches run multiple inserts and updates i would go for RAID 10 if your write ratio gets above 10%

    Does this mean you'll run without hotspare?

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