Re: [gentoo-amd64] Upgrading to Raid

[Joshua Hoblitt]

Supposedly the Areca cards offer much better RAID 5 performance.  Since
there is a driver in the -mm tree now I'm about to start testing a
24-port Areca SATA card.  I have *no* experience with them as of yet so
I can't recommend them.

    http://www.areca.com.tw/index/html/

-J

--
On Fri, Sep 02, 2005 at 09:22:34AM -0400, Matt Randolph wrote:
> 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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