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Re: LBA to File?

To: Stephen Lord <lord@xxxxxxx>
Subject: Re: LBA to File?
From: "Buzbee, James" <James.Buzbee@xxxxxxxxxxxx>
Date: Fri, 07 Mar 2003 08:18:32 -0700
Cc: Eric Sandeen <sandeen@xxxxxxx>, linux-xfs@xxxxxxxxxxx
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Stephen Lord wrote:
On Thu, 2003-03-06 at 16:50, Buzbee, James wrote:

The scary thing about what we are seeing is that the "grown defect list" on the disk is showing a lot of sectors in these two areas. It's almost as if we are wearing out the sectors in these areas by writing them so often. Strange but true ;-(

Jim



Ugh, yes these will be continually written to, the log in particular,
I like Eric's idea, but the scope of that is fairly drastic and it
will only postpone the inevitable - you can probably do the math to
work out how long the drive will run before it runs out of bad
blocks to remap to. All running with alternating logs would do is
delay the drive becoming scrap metal. The reliability of these
devices may not be up to the load you are placing on them.
Not all ide drives are this bad, I have been running xfs on
the same ide drive for about 3 years now - but then I am
not running a PVR.

Some of these units are never turned off. The user turns off the TV and leaves the Set Top box on. They are running 24/7 recording at least one video stream, maybe two.


I suspect also you may have the write cache
turned off to avoid errors after a crash.
Possibly the way your app runs is making things worse. There is a script
in  the cmd/misc directory called xfsstats.pl you can watch log activity
with this. In particular xs_log_writes and xs_log_blocks. If log_blocks
is not a reasonable multiple of log_writes then you are doing a lot of
very small writes.

Thanks - We'll take a look at it.

Jim





Steve





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