Re: [gentoo-user] hp H222 SAS controller

[Paul Hartman <paul.hartman+gentoo@gmail.com>]

On Wed, Jul 3, 2013 at 2:29 AM, Stefan G. Weichinger <lists@xunil.at> wrote:
> Am 03.07.2013 00:42, schrieb Paul Hartman:
>> On Tue, Jul 2, 2013 at 2:56 PM, Stefan G. Weichinger <lists@xunil.at> wrote:
>>>
>>> Does anyone use that controller with gentoo?
>>>
>>> If yes, which driver/module does support it?
>>>
>>> I ordered one for a server and did not really check the facts ;-)
>>
>> Looks like it uses the LSI SAS2008 chipset (basically LSI controller
>> with HP branding), so you should enable kernel module mpt2sas
>> (CONFIG_SCSI_MPT2SAS) and probably some other SAS-related options will
>> be required as well if you don't already use them.
>>
>> I actually just installed a card with this same chipset in my Gentoo
>> machine yesterday! I have not attached disks to it yet, as I am
>> waiting for the enclosure to be delivered, but so far nothing froze or
>> burst into flames when the module loaded. :)  I even upgraded the BIOS
>> and firmware on the card from within linux and everything seems okay,
>> so far.
>
> Thanks a lot, Paul, for that feedback. Seems that you will be the first
> to really test it, my box will arrive next week, I assume. This will be
> an installation from scratch so no SAS-related stuff there already.
>
> I wonder if it makes sense to attach the disks to that adapter as well?
> This box will do amanda backups ... so there will be the amanda holding
> disk and it is important to have maximum speed between that holding area
> and the tape drive. I plan RAID1 on 2x2TB disks at least or maybe even
> RAID0 (it's a rather temporary storage area so the redundancy isn't that
> important). Testing will show!

Mine will be attached to an external 8-disk storage array with 2
external SAS cables (4 disks per cable). I had a 5-disk 8TB software
RAID5 in my computer that I had to remove due to an unplanned
motherboard upgrade. Right now the disks are in a cheap external
5-disk eSATA/USB JBOD enclosure plugged into the eSATA port on my
motherboard, but it's not able to access all disks at the same time,
so the RAID5 performance is awful. Around 10-20 MB/sec on writes and
max 50MB/sec on reads. (It was previously 100MB+/sec for both
operations.)

In the eSATA enclosure, a single scrub (check) of my array takes FOUR
DAYS to complete! I worry about what will happen if I have to replace
a disk, the rebuild would take forever... what if there is a power
outage and my UPS battery only lasts around 30 minutes?

I bought two of the lowest-quality 4tb Seagate drives for US$140 each
on sale and plan to use them to make a backup copy of my files from
the RAID onto those drives. So far I have never made a backup of my
RAID because I never had enough storage space to duplicate it all.
"RAID is not a backup" has been repeating in my head for all these
years. Horror stories about a corrupt filesystem, or 1 bad sector
causing the whole RAID5 rebuild to fail. Now that I will have extra
drive bays, maybe I can add a second parity drive and try to do an
online upgrade from RAID5 to RAID6. I definitely want to make a good
backup before I try that...

I am hopeful that the SAS controller and enclosure should give me high
performance again! I will let you know how it goes.

BTW, I am using the latest 3.9 series linux kernel.