On 03/07/2011 09:00 AM, Nico Kadel-Garcia wrote:
>
> On Sun, Mar 6, 2011 at 10:07 PM, Charles Polisher<cpolish@xxxxxxxxxxxx> wrote:
>
>> > https://secure.wikimedia.org/wikipedia/en/wiki/Fakeraid#Firmware.2Fdriver-based_RAID
>> > covers fake RAID.
> Ouch. That was*precisely* why I used the 2410, not the 1420, SATA
> card, some years back. It was nominally more expensive but well worth
> the reliability and support, which was very good for RHEL and CentOS.
>
> I hadn't been thinking about that HostRaid messiness because I read
> the reviews and avoided it early.
>
Here's the latest info which I'll share ... it's good news, thankfully.
The problem with terrible performance on the LSI controller was traced
to a flaky disk. It turns out that if you examine 'dmesg' carefully
you'll find a mapping of the controller's PHY to the "id X" string
(thanks to an IT friend for that tip). The LSI error messages have
dropped from several thousand/day to maybe 4 or 5/day when stressed.
Now the LSI controller is busy re-syncing the arrays with speed
consistently over 100,000K/sec, which is excellent.
My scepticism regarding SMART data continues ... the flaky drive showed
no errors, and a full test and full zero-write using the WD diagnostics
revealed no errors either. If the drive is bad, there's no evidence
that would cause WD to issue an RMA.
Regarding "fake raid" controllers, I use them in several small machines,
but only as JBOD with software RAID. I haven't used Adaptec cards for
many years, mostly because their SCSI controllers back in the early days
were junk.
Using RAID for protecting the root/boot drives requires one bit of extra
work ... make sure you install grub in the boot sector of at least two
drives so you can boot from an alternate if necessary. CentOS/SL/RHEL
doesn't do that for you, it only puts grub in the boot sector of the
first drive in an array.
Chuck
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