RAID 5 question

 
emily_3
Frequent Advisor

RAID 5 question

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.
8 REPLIES 8
Devender Khatana
Honored Contributor

Re: RAID 5 question

Hi,

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

HTH,
Devender
Impossible itself mentions "I m possible"
Leif Halvarsson_2
Honored Contributor

Re: RAID 5 question

Hi,
No, not without VxVM, there was no support for software RAID in LVM. The only option (whitout a RAID card) is mirroring.
emily_3
Frequent Advisor

Re: RAID 5 question

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

Re: RAID 5 question

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.
If it ain't broke, I can fix that.
emily_3
Frequent Advisor

Re: RAID 5 question

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

Re: RAID 5 question

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.
emily_3
Frequent Advisor

Re: RAID 5 question

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.
Devender Khatana
Honored Contributor

Re: RAID 5 question

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
Impossible itself mentions "I m possible"