topic Re: Striping Across AutoRAID Controllers in Disk

Striping Across AutoRAID Controllers

Craig Johnson_1 — Fri, 16 Aug 2002 20:57:25 GMT

I have a 12H with dual controllers. How does one go about striping the LUNS and LV's so that both controllers are used? I simply created the LUNS using SAM, four LUNS of 80GB each. I haven't been using any stripe options with the lvcreate command. If you watch the device, you see that only one controller is being used. PVLINKS are enabled, apparently done automatically when the VG is created by Sam.

Re: Striping Across AutoRAID Controllers

Edgardo M. Yumul — Sat, 17 Aug 2002 23:36:27 GMT

Hi,
From my understanding, the autoraid does the striping with mirroring (Raid 0+1) automatically when you create a LUN. This procedure is transparent to the one creating the LUNs. Those frequentlly used data are on Raid 0+1. The data which are not being used are automatically shifted to Raid 5.

I think on an autoraid, control X serves the primary controller and controller Y serves as a standy controller.

SAM automatically assigns the alternate link when you create a volume group on a specific LUN on the autoraid. I've tried doing vgreduce so that the alternate link becomes the first entry on the volume group on the lvmtab. Then after that I extend that device file which i removed so it becomes the second entry.

Re: Striping Across AutoRAID Controllers

harry d brown jr — Sun, 18 Aug 2002 00:48:51 GMT

Craig,

I used the search option and found at least these:

search string: lvcreate stripe luns autoraid

http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0xf3bd3a7b3682d611abdb0090277a778c,00.html
http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0x3bced08cc06fd511abcd0090277a778c,00.html
http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0x43e4f841489fd4118fef0090279cd0f9,00.html
http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0x25ce35067c18d6118ff40090279cd0f9,00.html

live free or die
harry

Re: Striping Across AutoRAID Controllers

Vincent Farrugia — Mon, 19 Aug 2002 04:34:07 GMT

Hello,

AutoRAID isn't meant to stripe across its controllers. It stripes between RAID 0+1 and RAId 5 automatically (hence its name). There are two controllers for high-availibility purposes, so that if one fails, the other one is used to maintain availibility. You cannot stripe across them.

HTH,
Vince

Re: Striping Across AutoRAID Controllers

Craig Johnson_1 — Mon, 19 Aug 2002 13:39:34 GMT

Great links Harry. I figured it had to do with using multiple LUNS and different physical paths to each LUN. Thanks!

Re: Striping Across AutoRAID Controllers

Roger_22 — Thu, 22 Aug 2002 13:40:13 GMT

The Model 12H stripes all LUNs accross all disks - for both RAID 1+0 and RAID 5 allocations. The 12H dual controller architecture is active-active, but only one controller processes ios to the disk, they both are active to the servers. All LUN are active thru either controller, so striping across controllers is possible. However, there will be no (or very little) performance value for doing so.