Quick Question on SAN mirroring

  • Hi all,

    I'm currently designing a new architecture/DR solution and my latest version is basically an active/passive SQL cluster on a SAN, using SAN mirroring to a second site. However, the identical boxes at site 2 will only be restored in the event of site 1 failing, in the meantime they'd be UAT, has anyone ever done this and is it feasible?

    Thanks,

    Lloyd.

  • Wouldn't the mirror be on standby? Therefore you wouldn't be able to run SQL against it. To get round this, you would have to create a snapshot against the mirror.

  • I don't know enough about SAN mirroring but I'm pretty sure that the database doesn't exist until the data is restored, I think the mirror takes snapshots of the data at interval, kind of like a SAN equivalent of log shipping.

  • Sorry, I thought you were implementing native SQL Server mirroring. I don't know enough about SAN mirroring to give a qualified answer.

  • Hi all,

    In SAN level, if you want to create replication contact your san box provider. Because it is vary from one to another vendor.

    In IBM sans, san replication is available. Flash copy concept is there. Flash copy and replication needs separate license. In flash copy all the data should be copied from one database to other database.

    San replication is replicate all the data in one san box to another san box. It needs separate fiber optical cable between those two san boxes.

  • the two types of (synchronous) SAN mirroring I have done the disks are not visible on the passive server, so I do not see how this would work.

    you should probably look at making the live cluster active\active and running the UAT instance on one node, live on the other.

    As you are going to the expense of SAN mirroring look at geo-clusters, each node is attached to different, mirrored SANS removing the SPOF of the disk array from the cluster. Requires windows 2008.

    ---------------------------------------------------------------------

  • Also, you will need licenses for your mirror site when SAN miroring. With SQL mirroring you don't as the databases are inaccessible.

  • the databases are inaccesible with SAN mirroring also. You don't need to license this server as it is purely for failover.

    ---------------------------------------------------------------------

  • I think it can vary by vendor as in our environment SQL has no idea it's being mirrored using HP SAN mirroring. You can access the databases if you need to.

  • Interesting. the two types we have used, EMC and IBM, the drives themselves are not visible on the server. Hence no need to license.

    I take it your database are read only?

    ---------------------------------------------------------------------

  • Yes they are read only but is so much quicker than using snapshots.

  • I have a similar question I was going to post that is close enough it should probably go here.

    I want to maintain a DR solution at AWS - I plan on having three VMs: MSSQL, Primary App/Terminal Server, *nix file server. My plan is to ship my full, diff, and tlog backups continuously to the unix file server on AWS while keeping the other two VMs asleep. Regularly I will boot up the other two VMs, patch them and slurp up the latest backups so the DB is close to current. Note that our production/live DB can be read-only at night, we do updates during the day only and it is okay for it to take several hours to spin up in case of DR [DR in my world is a natural disaster threat preventing staff from entering the office for safety reasons, or otherwise the building disappearing].

    In case of a DR event I'll boot up the DR MSSS box and apply full/diff/tlog and then turn on the app/terminal serving VM. Primary DB storage for the VM DB is a RAID5 array of virtual disks.

    Where am I going to trip up? Any suggestions / concerns?

    thanks!

  • your question has no referall to SAN mirroring so I don't see how it is close, you would be better off starting your own thread.

    why not just use logshipping?

    ---------------------------------------------------------------------

  • Based on our suggestion I've started a new thread.

    cheers

Viewing 14 posts - 1 through 13 (of 13 total)

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