Smart Array P400 Drive Failure

drivehphp-smart-arrayraid

I have a HP Proliant server with a Smart Array P400 RAID controller with 2 146 gb 10k SAS hard drives configured in a mirrored RAID configuration. Where could I find information regarding how a drive failure would affect this configuration? I am looking to see how this RAID configuration and hardware would react to a drive failure.

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I'd start here: HP Smart Array P400 controller - Questions & Answers

Honestly though almost every decent RAID controller acts the same in the case of a single drive failure in a two disk RAID 1 array. Since the Smart Array is a true hardware RAID controller either drive can fail and the OS will still work just about as fast as it did with two drives. If you had a software based RAID controller (Some of the cheaper Promise models for instance) then you sometimes need a boot diskette to force booting off the second drive.

The HP Smart Array's are very good RAID controllers, they are decently fast, very reliable and dead simple to use. They are definitely my favorite embedded RAID controller. One great feature they have is being able to pull a set of drives from one system and stick it into another for recovery etc. purposes. Lot's of other RAID controller get very confused when you present them an array pulled from a different controller, not so the Smart Array. They just work!

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Fran Garcia is correct, you can't just pick your own SATA disks with those controllers - HERE's the quickspecs to help you choose the correct disk part numbers.

Slow DL360 Smart Array P400i RAID

This is several questions in one, so I'll try to address a few of them.

I typically set Smart Array controllers to leverage a higher write cache ratio. I prefer to have 75% write cache because the OS (using the XFS filesystem) caches aggressively. XFS will make a difference, but what are you tuning for? Are you tuning to simply achieve specific numbers, or is there an application requirement driving this?

ext3 isn't the fastest filesystem out there. But you have some mount options (e.g. noatime) and journal settings you could tweak.
I don't use LVM, especially with HP controllers that can provide many of the same benefits.
You have I/O scheduler and elevator settings (e.g. noop or deadline, in this case) that can be tuned, but that's a function of your application's actual needs.

If you do go with XFS, try a basic config then try some advanced configuration settings. Over time, I've ended up with mount parameters very similar to the one in the original link.

I just ran the following iozone command line on an XFS partition contained within a DL380 G5 with P400i, 12GB RAM and 8 x 146GB 10k drives. The elevator is set to deadline:

Command line used: iozone -t1 -i0 -i1 -i2 -r1m -s24g

initial writers  =  348957.75 KB/sec
rewriters        =  335130.03 KB/sec
readers          =  132851.70 KB/sec
re-readers       =  137116.27 KB/sec
random readers   =   35774.41 KB/sec
random writers   =  250618.38 KB/sec

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Slow DL360 Smart Array P400i RAID

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