Where to put System DB's with SAN implementation?

  • This is my first experience with a SAN and we're about to migrate my SQL server to the SAN. The SAN is a nice product made by HP and worth about $200k, so it's not a cobbled together system...but I can't find any documentation to indicate if I should have the system level db's (master, msdb, and tempdb) running of the local system or the SAN.

    The next step is a cluster, which brings forward the same question...do I store the system level db's on the local or the shared storage device?

    Anybody have experience with this?

    Thanks,

    alex8675

  • You want your system databases on the SAN as you do the user databases - especially if you plan to turn this system into a cluster at some point later on.

    When doing the install, make sure to choose "Advanced" when you get to the actual installation page (sorry, don't have a screenshot). You can choose where to install the "Data" directory after you choose "Advanced". Make sure you choose a SAN drive at that point. It will install your system databases on the SAN drive, and by default any new userland databases will reside on the SAN drive. Myself, I point the installer at the root level of the disk. This way it creates the proper MSSQL.X directory at the root of the drive...

    Your friendly High-Tech Janitor... 🙂

  • In addition to what Gordon has stated, what kind of SAN did you get? Are you going with an EVA 4000/5000/8000/8100?

    When building the LUN's, pay particular attention to how the partition is created. You need to set the sector alignment (ALIGN=64) and format the drive with 64K allocation units.

    Jeff

    Jeffrey Williams
    “We are all faced with a series of great opportunities brilliantly disguised as impossible situations.”

    ― Charles R. Swindoll

    How to post questions to get better answers faster
    Managing Transaction Logs

  • We got a EVA 4100. I'm running some benchmark tests to see how much its going to increase IO performance. I'm going from 6 drives to 28, so I'm expecting some sizable gains.

    Thanks for the input.

  • I'm migrating an existing SQL2005 Server box to start using the SAN device. So, there's not really an installation.

    How do you recommend that I move the system level db's?

    thanks for your insight.

    Alex8675

  • Generally in a migration, you don't move the system databases (except for MSDB). You move everything but the master, model & tempdb. If you've already built the new system and the system databases are not on the SAN drives; I (myself) would re-install the sql server and change the system db location as noted above during install. There have been reports of service pack installation issues if you move the resource databases from thier default installation location (like you would in this scenario). This could be a critical point later on when you want to service pack, and or when you want to cluster the existing system.

    If you can, I would take the time to re-do the new servers installation.

    A basic migration from one to another server is as follows:

    1: Backup & restore your userland databases to the new system.

    2: Backup and restore MSDB if you need to (to migrate DTS/SSIS/jobs). There are some things to perform after the MSDB restore (BOL has all the pertinant info). This isn't an absolute neccessary step, it depends on your migration requirements.

    3: Use the sp_helprevlogin procedures (Google) to migrate your logins from the old server to the new.

    That's a pretty basic rundown of the base steps involved to perform a successfull system to system migration. There are quite a bit of details to those individual steps though.

    The good new is, that you can backup and restore on the new system to your hearts content. You have the ability to test and refine your migration process at will, for the most part.

    Edit:

    I misread your post (it's still early here on a Sat. morning). :hehe: I'll leave the migration points up though for anyone interested...

    So you're just adding a SAN drive to an existing installtion? BOL has documentation on how to move the system databases, it's fairly straightforward. However, in that case, I think the biggest hurdle you're going to have is if you move the resource databases and you run into issues trying to service pack the instance. Also, you _may_ run into issues with it if you want to try and upgrade the server into a cluster later on - I (myself) wouldn't really speculate on that without some testing on another system though.

    Your friendly High-Tech Janitor... 🙂

  • Thanks for your insight...I'll look into this a little further, but I'll probably stick with the system db's on the current system for this stage of the process.

    The next step is a cluster, I get new machines for that and I can do clean installs.

    Thanks again for the help,

    alex8675

Viewing 7 posts - 1 through 6 (of 6 total)

You must be logged in to reply to this topic. Login to reply