PowerVault 221S & PERC4/DC - Maximum logical disk size?

Question

I have PowerVault filled with 14 ~286GB drives connected in dual channel mode to PERC4/DC.
I'm trying to create a single logical drive with a size of ~3.7TB ((14-1)*286), using a RAID5 mode, but I failed, because PERC bios always creates two logical drives, splitting them at 2TB limit. I know I can later join them in software RAID0, but can I do so in hardware?
I've tried different modes, such as RAID5(7drives)+RAID5(7drives) but anyway it creates two logical drives with one of 2TB, and second as all that remains.
Is logical drive can be more then 2TB??

P.S.
All that I do from Ctrl-M utility. Will management software provided with it do the same? (can't remember exact name)

Message Edited by mlesin on 08-19-200612:54 AM

Dev Mgr · Answer

Try the last firmware for the PERC to see if that will do it (assuming you're not already on the latest firmware).

A likely reason the 2TB cap is/was there is because most older OSes cannot use disks larger than 2TB.

Disks are usually partitioned with MBR (Master Boot Record). This has a cap of 2 TB by design. For larger disks GPT was created (GUID Partition Table). Windows 2003 SP1 (and R2 therefor too), RHEL 4 and SLES 10 (9 maybe too) (probably any Linux flavor on a 2.6 kernel, but I'm not 100% sure on that) can support GPT.

Another option would be dynamic disk (Windows 2000/XP/2003 only).

It's very possible that LSI (manufacturer of Dell's PERC4 solutions) and/or Dell have opted not to offer 2 TB capabilities yet, as there are too many systems running older OSes still. Also, a disk of this size wouldn't be bootable (though I wouldn't think you'd be trying to boot off of a PV221).

Message Edited by Dev Mgr on 08-23-200606:15 AM

mlesin · Answer

Just to be sure I understood you right, if latest firmware wouldn't support logical disks larger then 2TB, I'll have no chance to get a single hardware without combining 2 logical volumes in software?
As far as I got it, logical disk is a prior structure to partition (where MBR or GPT can be applied)?
I'm planning to run SuSE 10.1 x86_64 on it, it supports LVM, is it what I need?

P.S. Sorry for possible stupid questions, I'm just a bit unfamiliar with this...

Dev Mgr · Answer

I would actually recommend smarter disk management and set up 2 or more seperate smaller virtual drives.

Here is a scenario: System has a problem of some kind and hangs/bluescreen/core-dumps. You force a reboot and the system wants to run a checkdisk/fsck on your 4TB partition. Be ready to be without the system for several days.

Now you set it up as 4 x 1 TB and the same thing happens. The odds on needing to check all 4 drives are pretty low, so it may just need to check on 1 or 2 of the virtual disks, saving a lot of time before the server can be online again.

I can't tell you not to use very large disks, but my experience is that larger disks is not necessarily the best way to go.

Mark_A_Smith · Answer

All Perc controllers previous to the Perc5 only support 2TB per array.

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PowerVault 221S & PERC4/DC - Maximum logical disk size?

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