Mirrorux for Data Disk on Ds2300

[Leon Shen]

Hi All,

I had a rp5405 server connect 1xDS2300. The DS2300 contain 8 hard disks and I would like mirror the external disk.

My question is if I want 4 disks become 1 virtual Group and mirror to another 4 disks and How I am going to do it.

Thanks
Leon

[Wim Rombauts]

You do that by using "physical volume groups"

Put four disks in one physical volume group
Put the other four in a second physical volume group

I think you can do that with vgcreate, otherwise, use SAM, I'm sure he can easily handle this.

Create your logical volume with the "-s g" option (PVG-strict mirroring).

[Mark Grant]

Important to realise you don't mirror disks. You mirror logical volumes. So, you put all eight disks in your volume group. Create logical volumes on four of them and mirror them with lvextend specifying which disk the mirror should reside on.

This number of disks is almost worth using Physical volume groups though. Put four disks in one physical volume groups, the other four in another. Make all logical volumes "PVG-strict" allocation. Then, when you mirror them, you guarantee that the mirror will be on another group of disks. This only really saves giving the disk names though.

[Joseph Loo]

hi,

i think Leon wants some steps on this which i requested him to look at Document id: KBRC00012000, from HP:

http://www2.itrc.hp.com/service/cki/docDisplay.do?docLocale=en_US&docId=200000072951457

the steps given in this document should be sufficient and he probably wants a second opinion, so please indulge him.

regards.
(p.s. sorry, Leon, i made you post this so many times)

[Bharat Katkar]

Leon,

To brief the procedure:

1. Create 4 disk LUN1
2. Another 4 disk LUN2
3. Now create LV's on LUN1 and LUN2
4. Create files systems on LV
5. Create mirror's of LVs on LUN1 to the LV's of LUN20 using lvextend -m


Mirroring down by lvextend command is Software mirror and that down in RAID box is hardware mirror. Also take a look at loo's link, there are all necessary details.

Hope this helps.

[Joseph Loo]

hi,

since you are using DS2300 where you will have 7 empty slots so, just in case if you need to extend the striped and mirror logical volume. read Document id: KBRC00008016:

http://www2.itrc.hp.com/service/cki/docDisplay.do?docLocale=en_US&docId=200000066374278

regards.
(p.s. thanks for the points, you played a small part in helping me achieve my pointy hat.)

[Ted Buis]

It is possible to split the bus on the DS2300 by adding a second redundant controller (A6491A) and a second SCSI HBA to the rp5405, and put one each side of the mirror on separate buses. This will provide the highest performance (slightly) and best availability, since you can then tolerate a SCSI HBA failure or DS2300 failure. Since there are some active components that "split" the bus, it isn't as highly available as two DS2300 enclosures each with 4 drives, but would be an improvement if you don't have it already.