Re: [Vserver] clean-up hash directory

From: Roderick A. Anderson <raanders_at_acm.org>
Date: Fri 08 Sep 2006 - 19:01:39 BST
Message-ID: <4501B003.20908@acm.org>

My thanks to Corey and Daniel. This explains a lot. I love the vserver
incantations but really like it when I know what they are doing instead
of having to treat them as magic.

My thanks to all those that make Linux-Vserver such a great tool.

Rod

-- 
Corey Wright wrote:
> On Fri, 08 Sep 2006 06:46:17 +0200
> Daniel Hokka Zakrisson <daniel@hozac.com> wrote:
> 
> 
>>Roderick A. Anderson wrote:
>>
>>>Corey Wright wrote:
>>>
>>>
>>>>i was curious if vhashify cleaned up after itself (delete orphaned
>>>>instances of files in hash directory), and it appears it doesn't.
>>>>these commands should do the job. well, technically this just lists
>>>>files with a
>>>>hardlink count of 1 and prints the total size in bytes of all listed 
>>>>files
>>>>on the last line (so you know how much space you are saving).
>>>>
>>>>find /etc/vservers/.defaults/vdirbase/.hash/ -type f -printf "%n %s 
>>>>%p\n" |
>>>>grep '^1[[:space:]]' | awk '{ sum += $2; print $3 } END { print sum }'
>>
>>You could easily eliminate the grep by using -links 1 in the find command.
> 
> 
> thanks.  guess i didn't see that in the man page (and i've never had reason
> to mess with hardlinks before, especially using find).
> 
> 
>>>>to delete those listed files, add to the end:
>>>>   | while read FILE; do rm -f ${FILE}; done
>>
>>Would be far more efficient to use -print0 | xargs -0 rm -f.
> 
> 
> correct, but that would have required me to offer two commands:
> - one for calculating total size of all orphaned hardlinks (people, me
> included, like to see the effects of what they are doing quantified for
> purposes of justification and "warm fuzzies")
> - another for deleting orphaned hardlinks
> 
> not an issue for me or hopefully most people, but i wanted to keep my
> instructions as simple as possible (and just adding another piped command
> is easiest as it simply builds upon what was already instructed).  i try to
> keep it KISS (Keep It Simple, Stupid) when dealing with people (the entire
> mailing list) of unknown experience levels.
> 
> of course, also make sure you don't have a file in the current directory
> named the same as the total size (in bytes) of all the orphaned hardlinks
> or that file will be deleted (as it is the last line printed by awk), but i
> didn't worry about that as the statistical odds are pretty low. when i sent the
> email i wondered if anybody was going to reply noting that, so i already
> had this response ready. :-D
> 
> so yeah, my suggested commands are not "production quality". ;-)
> 
> 
>>>Did you hear anything on this?  I ran the query on a 12+ guest system ( 
>>>all FC5 ) and it ran for well over a couple of minutes before I got 
>>>tired of watching the output.  This leads me to think I've got lots of 
>>>orphans.  I'd like to get rid of them ( Save the inodes! ) but want to 
>>>understand what I'm doing first.  Rather not fubar a live system.
>>
>>This should be a perfectly safe command, I always run some cleanup after 
>>hashifying my guests.
> 
> 
> i hashify my guests daily as part of a daily-maintenance cron job as i
> often forget after installing/upgrading a package and my vserver is not too
> heavily loaded.  i might toss this in there too.
> 
> 
>>>I'm not sure I fully understand how vhashify works.  Where are the 
>>>actual files located.  Are the entries in
>>>    /etc/vservers/.defaults/vdirbase/.hash/
>>>links to the actual files and then each guest links to these -- links?
>>
>>Those would be the actual files (the file in the .hash directory is 
>>created by vhashify as a copy of the file it's hashifying), and vhashify 
>>then creates links to those in the guest(s).
> 
> 
> roderick, if daniel's explanation is too succinct for you, i can reference
> a few of my prior postings where i ramble on forever trying to stumble
> through my own hypothesizing of how hashifying works. ;-)
> 
> thanks daniel.  your expert knowledge on vserver is always welcomed and
> appreciated (no matter how bad it makes me look).
> 
> corey
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Received on Fri Sep 8 19:02:33 2006
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