mke2fs -j goes nuts on 3Ware 8506-4LP

[Mark Watts <m.watts@eris.qinetiq.com>]

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I have a 3Ware 8506-4LP controller with 4 250GB Maxtor SATA drives, in a 
raid-5 configuration (64K blocks)
System is:
Dual Opteron 246 (2GHz)
2GB RAM
Tyan S2875 motherboard

Kernel: 2.6.8-rc2 (pre-empt is ON)
Rest of OS: Mandrake 10.0 AMD64 edition.

When I execute a mke2fs -j /dev/sda7  to format a 600GB partition on the raid 
as ext3, the system slows to a crawl.

Basically, the inode creation goes fine for the first 1000 nodes or so, then 
starts slowing to about 1 node per second.

According to 'top' the systems 'buffers' value is almost all my ram and both 
cpus are at almost 100% in I/O wait.

The system load will start to climb and it eventually hit ~15 before I got 
bored and rebotoed.

X is totally unresponsive although 'top' does refresh occasionally in a 
konsole.


I do understand that the 3Ware 8506 cards arent exactly stellar at raid-5 (we 
see ~22MB/sec write and upto 80MB/sec read if we're lucky) but surely a 
simple format of a filesystem shouldn't tie up the system like this?

Would a different card (3Ware 9500 series or LSI Logic MegaRAID) help here?

Cheers,

Mark.

P.S. As I write this, I'm doing an sa-learn (spamassassin) over 14k messages 
and the system is a little sluggish even though gkrellm is only showing 
~1MB/sec on the 3Ware, so I'm guessing these are just pants cards in general.
Periodically runnung 'sync' helps for a while but it fades again after that.

- -- 
Mark Watts
Senior Systems Engineer
QinetiQ Trusted Information Management
Trusted Solutions and Services group
GPG Public Key ID: 455420ED

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