Re: [SLUG] disk throughput vs cron

From: Eben King (eben01@verizon.net)
Date: Sun Dec 03 2006 - 22:54:41 EST


On Fri, 1 Dec 2006, Chris Mathey wrote:

> Mike Branda wrote:
>> On Thu, 2006-11-02 at 12:54 -0500, Eben King wrote:
>>> On Thu, 2 Nov 2006, Rich Morgan wrote:
>>>
>>>>> I run a disk-to-disk copy every morning at 5am, invoked by cron. Every
>>>>> now and then, I see a drop in throughput (today it was from ~45 MB/s to
>>>>> ~34 MB/s, from 5:01:30 to 5:08:30). How can I find out what's running
>>>>> at this time and slowing down the copy? I already found the stuff in
>>>>> /etc/crontab, and I moved that from 6:xx to 7:xx. I checked crontabs
>>>>> for root and eben (news has none), nothing about that time.
>>
>> check out
>>
>> /etc/cron.daily
>> /etc/cron.hourly
>>
>> etc...
>>
> Are you doing a disk to disk copy to backup files?

Yeah.

> Have you tried rsync?

I played with it, but couldn't think of a way to have it do something
appropriate with unmounted partitions, unused (but still consistent)
partitions, and dealing with repartitioning. If it copied an unused
partitions, I'd be no worse off than I am now, I guess.

> I use it to copy changed\new files to a second disk. I
> then rotate them out to a USB drive. Much more efficient\easy than cp.

Efficiency, I very much agree. Ease, not so much. "dd if=/dev/hdc
of=/dev/hde" is pretty easy...

-- 
-eben    QebWenE01R@vTerYizUonI.nOetP    royalty.no-ip.org:81
PISCES:  Try to avoid any Virgos or Leos with the Ebola
virus. You are the Lord of the Dance, no matter what those
idiots at work say.  -- Weird Al, _Your Horoscope for Today_
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