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

[Alex Bligh - linux-kernel <linux-kernel@alex.org.uk>]

Adam,

> > All seems to go well until I try and do mke2fs. This appears to work,
> > and tries to write the inode tables. However, at (about) 3400 inodes
> > (of 11176), it slows to a crawl, writing one table every 10 seconds.
> > strace shows it is still running, and no errors are being reported.
> > However, it seems very sick.
>
> Do you have cache turned on or off?  If it's off, try turning it on.

On. I started again (deleted the units etc.) which I'd done before.
I am not sure quite what I did different this time. Now I get 270Mb/s
on dbench, 100Mb/s (approx) on a solid contiguous write (dd), which
is well into the field of uninspiring but not as daft as 7Mb/s. I had
rather expected that h/w RAID 5 would give me faster reads, and only
slightly degraded writes, compared to a single disk of the same type
plugged into the motherboard SATA.

However, dbench puts the (dual opteron 275) machine into 99% system
state. Is that normal? Surely it should be in i/o wait.

I /think/ what had happened is this: When I press F8 to exit the
BIOS, it did not initialize the array (this is in accordance with the
manual, it being deferred). Despite leaving the machine idle in the O/S
for 2 days, it didn't start initializing the array. Running the mkfs
started the initialization (would that make sense)? The second time
I ran mkfs, I may have already (somehow) triggered it to start earlier.

I shall try and work out some soak test I can run on it this w/e.

--
Alex Bligh
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