Re: File transfer speed slows 10x and more after reaching 1TB in size

On Tuesday, February 9, 2016, 22:42:02, alanb wrote:

> In my case the CPU usage was normal throughout the whole process. Are
> you experiencing high CPU usage when the problem surfaces?

Yes, I first noticed that jfsCommit was using around 90-100% of a
core, and that the backup suddenly slowed down.

> In my case, I noticed that my disk was "thrashing" about while in the 
> slow state, the noise made by the drive in an open case was very 
> noticeable. When it was transferring normally, the disk was nearly 
> inaudible. Also the approximate 1TB threshold seemed to be a sharp 
> dropping point, performance quickly degraded once that point was reached.

I can't speak of disk thrashing, because both computers where I
noticed this are in different rooms than where I normally work.

> I will need to use something for these large images, the problem makes
> JFS unusable and the thrashing may even destroy my HD. My next test is
> to switch to ext4 or XFS and do a transfer of the same 2TB image file.

I switched to xfs on one computer, and it seems to perform well (one
of the backup images is currently 1043GB - I couldn't take this backup
with jfs at all, but there was a noticeable speed increase with
another, where the base image is 140GB - on jfs it took about an hour
to create increments and merge the oldest increment into base, while
it now takes about 10-15 minutes).

-- 
< Jernej Simončič ><><><><>< http://eternallybored.org/ >

If you mess with something long enough, it'll break.
       -- Farmer's Comment


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