Re: 3ware 9550SX problems - mke2fs incredibly slow writing lastthird of inode tables

From: Alex Bligh - linux-kernel
Date: Tue Nov 01 2005 - 19:11:21 EST




--On 01 November 2005 18:13 +0100 Florian Weimer <fw@xxxxxxxxxxxxx> wrote:

In my experience, the 3ware SATA controllers which are not NCQ-capable
have very, very lousy write performance with some drives, unless you
enable the write cache (which is, of course, a bit dangerous without
UPS or battery backup on the controller).

Not to sound like the a 3ware chearleader, but this card does support
NCQ.

Oh. I didn't know whether this particukar controller supported NCQ or
not.

It even supports SATA-3, not much good that it does me.

I managed to format it reiserfs in the end. dbench (yes I know it isn't a
great benchmark) gives me a write speed of 7Mb/s compared to 700Mb/s if one
of the disks in the array is attached to the motherboard SATA controller.

7Mb/s is quite stunningly appalling. I realise the release notes warn of
slow writes, but that's just daft! I have a few bits in my setup to check
before I start pointing the finger comprehensively. It may (for instance)
be a large partition problem (suggested on the ext2 list).

I'm taking it that it works at least for some people (did you test write
speed Lawrence?).

--
Alex Bligh
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