topic Re: RAID 5 question in Operating System - HP-UX

RAID 5 question

emily_3 — Tue, 21 Jun 2005 04:44:26 GMT

Hi everyone,

I only have a DS2300 disk array together with a L class server. Can I do RAID 5 without the any RAID hardware adapter and VXVM software? Thanks.

Re: RAID 5 question

Devender Khatana — Tue, 21 Jun 2005 04:58:02 GMT

Hi,

LVM do not support this. It supports stripping but not raid5. It requires a Hardware Raid Adapter or a VXVM product.

HTH,
Devender

Re: RAID 5 question

Leif Halvarsson_2 — Tue, 21 Jun 2005 05:47:19 GMT

Hi,
No, not without VxVM, there was no support for software RAID in LVM. The only option (whitout a RAID card) is mirroring.

Re: RAID 5 question

emily_3 — Wed, 22 Jun 2005 20:40:43 GMT

So can i do mirror + stripping for my case? If can, what's the step? Thanks a lot.

Re: RAID 5 question

A. Clay Stephenson — Wed, 22 Jun 2005 21:01:55 GMT

You can do extent-based striping if you have the optional Mirror/UX product but I wouldn't bother. I've never seen a measurable performance improvement from its use. The problem is that the smallest possible physical extent size is 1MB (which limits the maximum size of the physical disks you can use) but 1MB is much too large to be a good stripe size to spread the i/o. In any event, you wouldn't want to do RAID-5 for performance; the effect for writes is exactly the opposite.

Re: RAID 5 question

emily_3 — Wed, 22 Jun 2005 22:23:40 GMT

Thanks for your advice. But is there any way that I use lvcreate -I -i option, and then implement mirror?

Re: RAID 5 question

Patrick Wallek — Wed, 22 Jun 2005 23:35:28 GMT

Nope, that is not possible.

The '-I -i' and '-m' options of lvcreate are mutually exclusive at this point. If you want true striping and mirroring then you have to go the VxVM (Veritas Volume Manager) route.

Re: RAID 5 question

emily_3 — Tue, 05 Jul 2005 21:28:03 GMT

Hi,

I may plan to integrate a raid adapater (PCI-4-channel-ultra160 controller) in my L3000 server. But if without the VXVM software whether it can work with my DS2300 disk array ?
If can work, how much work I need to do after install the adapter? Something like what's the other software i need to install besides the driver for raid adapter? Any other configuration? Can someone advice me?

thanks.

Re: RAID 5 question

Devender Khatana — Tue, 05 Jul 2005 21:42:38 GMT

Hi,

After inslatting the RAID adapter you need to install the driver/utility for that card. Once done you need to configure all your disks from the scratch to configure new Logical devices whcih will be visible to host. You may leave OS part as it is and can have only data onto to DSXXXX array.

HTH,
Devender