[CentOS] RAID card selection - JBOD mode / Linux RAID

Thu Jul 19 16:24:19 UTC 2012
David C. Miller <millerdc at fusion.gat.com>

----- Original Message -----
> From: "Alan McKay" <alan.mckay at gmail.com>
> To: "CentOS mailing list" <centos at centos.org>
> Sent: Thursday, July 19, 2012 5:21:17 AM
> Subject: Re: [CentOS] RAID card selection - JBOD mode / Linux RAID
> On Wed, Jul 18, 2012 at 6:44 PM, SilverTip257
> <silvertip257 at gmail.com> wrote:
> > That's going to really drag if you have to configure a RAID0 for
> > all
> > 48 disks ... it'd be much easier if you could directly communicate
> > with the drives.  I've set up at most five or six RAID0 devices on
> > one
> > host and it's not particularly enjoyable!
> Well using the command line tools it is not bad at all - but my
> question remains unanswered - how many logical devices can your card
> have?  I've hit my limit at 24 but I have 48 drives.  So I need to
> find a card that can do 48 logical devices.
> thanks

I use an LSI 9200-8e PCIe host bus adapter card for my SAS JBOD's. It has nothing but two standard SFP connecters for connecting external JBOD. No fancy hardware RAID or anything is done by the card. I can see up to 512 SATA/SAS drives connected to the card via SAS JBOD enclosures. Drivers a re built into the Linux kernel. Drives are seen raw in Linux so you can use smartd and smartctl to monitor them. There is also an HBA 9200 series that does internal connections too. Most of LSI's non HBA cards that do RAID do NOT support pure JBOD.