2 Replies Latest reply on Mar 11, 2012 5:40 PM by kimic@seznam.cz

    optimal  HDD setup for medium DB/Application server using SR1625URR




      I am doing config specs for SR1625URR server, currently with 2x Xeon E5645 and 48GB RAM (using 8GB modules), with option to add another 48 using same modules.
      Now the tricky part is the IO,  with a database/application server, this is the main  performance bottleneck as long the DB indexes fit in the memory.
      I was checking other options such as SSD, which look like outperform SAS easily for DB transactions effectively 1SSD drive as 1 whole SAS raid
      Would this setup be good choice instead?
      • 2-4x Intel SSD 520 (120GB)  w/out any RAID   (DB tablespace on each drive)
      • 2x SATA 300GB/600GB in RAID1  (system, temp folders, periodic backups of the DB files on the SSD drives, lets say 1-3 hrs or any shorter interval not affecting the performance)
      Or should I rather drop this, and go with SAS drives only (replacing all parts to utilize 6G SAS, add extension cards/backup batteries for RAID10) ?
      The SSD setup would have killing performance, but the problem is the zero fail recovery, working only from the last backup on the HDD (depending on the backup interval) and more important it requires instant manual interaction unlike RAID1 mirror, to fix the problem. Using RAID1 with SSD has still some problems, so its not much used it seems.
      Anybody has experience with such hybrid setup? if it is good, or should be avoided because of the missing uptodate online mirror?  I like how the SSD drives work with the DB, but I am not sure about proper setup for fast fault recovery
        • 1. Re: optimal  HDD setup for medium DB/Application server using SR1625URR

          It seems RAIDed SSDs would be the best.  What issues have you heard of, with that configuration?

          • 2. Re: optimal  HDD setup for medium DB/Application server using SR1625URR

            for RAID1 the SSD disks cant use Trim so they degrade faster, my SSD experience is limited still. I read that also Raid5/0 is nice with SSD  but I would like to find some real usage feedbacks first before i set it up. From what I read that unless the SSD disk die completely due hw failure, the other fail scenario is they switch to readonly mode. Sometimes its also some temporary situation due firmware problems.

            Now in case such event happens, I know how the controller would work with SAS/SATA disks, but unsure about the SSD especialy with the read only mode and raid5.

            The RAID5 with SSD is safer or same/worse compared to regular disks? 


            I was thinking that instead going to pure SAS 15K  in RAID10, I can try use hybrid setup such as SATA+SSD or SAS+SSD that can bring increased performance. So if somebody has already good RAID1 or RAID5 setups working with SSD, I would like to hear.