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Database Server Configuration

  • November 10, 2004 at 7:54 am

    #182622

    Hello, I am writing a proposal for a database config. for my company. We are a small company with a far from ideal database server set up. At present, we have MySQL and MSSQL Server 2000 residing on a single disk partition.

    I know that RAID is recommended for a database server for performance, fault tolerance, reliabilty and availability. However, I am not sure what set up would be more appropriate for our needs (cost is also a consideration). I have outlined the options below, and would greatly appreciate anyone to tell me why one setup is better than the other:

    1) RAID 10 - combining the benefits of striping with mirroring (divided disks into sets 2 with RAID 1 and mirrored across the sets)

    2) RAID 0 - striping for performance, but replicated across different disks on a separate or even same server as a backup utility. Although similar to 01 or 10, no rebuilding of the array would be required and we could simply switch to the replicated version.

    Can someone explain to me what the advantages and disadvantages are of the two above configurations please??????

  • November 10, 2004 at 8:08 am

    #529625

    See http://www.prepressure.com/techno/raid.htm

    or http://compreviews.about.com/library/weekly/aa-RAID-Pg1.htm

    for a pretty decent comparison of RAID.   On most of our servers the OS is set up as RAID 1 (mirrored) and there is a SAN attached storage for the data which is set up as RAID 5 - so we can withstand the loss of a disk drive; which has happened.

     

    HTH

    Francis

  • November 10, 2004 at 8:28 am

    #529633

    Thanks for replying Fhanlon,

    I have got quite a good grip of the different RAID levels. However, I am more confused about the differences between RAID redundancy and database replication. We need a system that is fault tolerant, yet also has a similar read to write ratio performance (which mirroring does not offer). We have a single disk server waiting to be configured, but I am trying to argue that RAID is a better option (for fault tolerance and performance). Although mirroring provides back up and improved read performance, write performance is only comparable to that of a single disk solution.

    I am presently looking at RAID 10 as it offers higher fault tolerance than 01 (more drives can fail due to the smaller set sizes) and excellent read and write performance for both random and sequential access. However, as my colleague mentioned, why not go for RAID 0 simply for performance, but replicate the data (I do not fully understand replication as I have never actually done it) to another RAID 0 array, whether it be on the same server or a separate one. That way, we do not have to fork out the costs for a high-end controller (for RAID 10), and would not need to attempt to rebuild the array, as we would have another system, exactly the same, replicated.

    Maybe what I am asking is what are the differences and the benefits of a RAID solution compared to replication? There may be no comparison and be used for completely different purposes, but can you please tell me what they are???? Sorry for not simply looking it up myself, but I have so many other things to be getting on with - and I like to take advantage of all you brain boxes out there! Thanks in advance!

  • November 10, 2004 at 8:51 am

    #529637

    Replication and RAID are two different things although I agree similar functions can be achieved.  RAID is usually set up to guard against a local hardware failure.  Replication is set up to allow you distribute data and stored procedures amoung servers either in the same physically location or geographically separate.  Replication can be used to push all or a part of your database to another server for  reporting, sharing data or even possibly for disaster recovery.  Although this may be like buying a Mercedes to drive to the corner store.  (ie overkill)   Disaster recovery is different than "my disk failed".    Replication is higher cost that RAID 10, and has a performance impact even if minor.   You need another server and maybe another SQL license depending on setup.  If you are doing this for disaster recovery this server needs to be physically separate - another building?  On the other hand a good RAID system with sufficient backups (moved to tape and taken offsite) may cover off your needs.  Look at replication costs to see if its affordable.

    Francis

  • November 10, 2004 at 8:53 am

    #529638

    Thanks ever so much - just the reply I was searching for!!! I can use this reasoning in my report!

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