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From: John Goerzen <jgoerzen@complete.org>
To: Tomasz Chmielewski <tch@virtall.com>
Cc: linux-btrfs@vger.kernel.org
Subject: Re: Lots of trouble hanging when rm files with many extents
Date: Mon, 21 Oct 2013 08:47:48 -0500	[thread overview]
Message-ID: <52653084.8050106@complete.org> (raw)
In-Reply-To: <20131021133644.172387f5@virtall.com>

On 10/20/2013 11:36 PM, Tomasz Chmielewski wrote:
>>> I'll do some more tests with lots of extents to see if it's
>>> reproducible here as well.
>> Interestingly, I've generally had qgroups enabled here as well,
>> possibly on all of these systems.  Could that be the culprit?
> Possibly.
>
> Is there a reliable way to create files with many extents? I've tried
> playing with fallocate, but couldn't create files with too many extents
> with it.
I could do it quite reliably by storing a VirtualBox VM hard drive image 
there, then running a Windows Update inside the VM.  Instant 
fragmentation ;-)

Another approach could probably be to write a C program that writes 20GB 
to a file, then seeks to random places within it, writing chunks of data 
within them.

I could probably whip up such a thing if the debuggers need it.

John

  parent reply	other threads:[~2013-10-21 13:47 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-21  4:36 Lots of trouble hanging when rm files with many extents Tomasz Chmielewski
2013-10-21  9:58 ` Duncan
2013-10-21 13:47 ` John Goerzen [this message]
  -- strict thread matches above, loose matches on Subject: below --
2013-10-22  9:40 Tomasz Chmielewski
2013-10-20 14:51 Tomasz Chmielewski
2013-10-21  3:40 ` John Goerzen
2013-10-19 23:12 John Goerzen

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