topic SLVM vs ASM in Operating System - HP-UX

SLVM vs ASM

jpcast_real — Fri, 01 Feb 2008 07:08:25 GMT

Hello,

I am planning to move our DB 9i which runs inside a cluster package, MC/SG to a real application cluster. Several options I have as far as I see:

- SGeRAC extension , which i think includes SLVM

- use directly ASM then I suppose I do not need the SGeRAC extension but I doubt if how can I use multipathing and mirror disk between EVAS with ASM . If I use ASM can I include the RAC instances in a cluster Package.

- forget SG and use ASM and the Oracle cluster.

Please experts, tell me your experiences.

Thanks in advance

Re: SLVM vs ASM

Duncan Edmonstone — Fri, 01 Feb 2008 07:35:23 GMT

See my last post in this recent thread:

http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=1198974

Also - are you using business copy in your EVAs for Oracle backup? This *will not* work with ASM, as there is no supported way to get ASM to stop metadata updates during a business copy mirror split - this can result in inconsistencies between ASM metadata on different vdisks that are split ats slightly different times.

Can I ask why you want to migrate to RAC from a single instance database? Many people think they will get higher availability/better performance from RAC, and in my experience that isn't always the case... if you don't have pretty hot DBAs and the capability to tune/alter the construction of SQL statements that hit the database (i.e. you can get at the application source code), I'd think twice.

HTH

Duncan

Re: SLVM vs ASM

jpcast_real — Fri, 01 Feb 2008 08:25:19 GMT

Hello,

we need RAC because we can not allow more than 5 minutes of system down and when the OS where our system runs halts, we need at least 20 minutes for a failover and restart the whole application.

In this case this is not a matter of performance and I just wonder if ASM or SLVM is better.

I suppose that SLVM comes when you buy SGeRAC extension, but I do not have any experience about it?

We use business copy and secure path

Regards

Re: SLVM vs ASM

Emil Velez — Sun, 03 Feb 2008 00:34:38 GMT

Oracle 10GR2 supports CFS filesystem for a oracle database. ITs somewhat of the current rage. All of the flexability of filesystems with RAC. Best of both worlds.

IF you use ASM you loose the ServiceGuard cluster features that provides package addresses, packages in general, lan failover

YOu can create a multinode package to start the RAC instances on each node.