Re: [gentoo-amd64] Upgrading to Raid

[Matt Randolph <mattr@erols.com>]

That's valuable information indeed.  Since migrating from Windows to 
Gentoo I have had to abandon an old PATA RAID 5 card because its Linux 
drivers haven't been maintained in years.  I had thought about going the 
3Ware route, so I'm glad to hear about your experiences with their 
cards.  I guess I have some more homework to do.  Thanks for the heads-up!

Joshua Hoblitt wrote:

>I have a large number (more then a dozen) 3Ware 8500 and 9500 cards.
>The majority of these are 12-port SATA cards with RAID 5 volumes on
>them.
>
>Three quick observations:
>
>* Software RAID 5 on Linux WILL NOT remap bad blocks/sectors like a
>hardware RAID controller.  If you care about your data, software RAID
>simply isn't an option.
>
>* The RAID 5 performance of 3Ware controllers is terrible.  The 9500
>series cards can push 50-55MB/s with xfs and in the neighborhood of
>45MB/s with ext3 (with an enlarged journal, etc.) for sequential writes,
>random I/O is even worse.  The 8500 cards are about 10% slower compared
>to the 9500 once you fill up the on-card cache.
>
>* Neither xfs or ext3 are reliable on volumes greater then 2TB.  Nor can
>fdisk even partition them (but lvm2 can handle them).
>
>Cheers,
>
>-J
>  
>
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