I heard that ATLAS also has redundant files in different parts of the tree within a version.
-----Original Message-----
From: Testbed Support for GridPP member institutes [mailto:[log in to unmask]] On Behalf Of Sam Skipsey
Sent: 23 February 2011 09:13
To: [log in to unmask]
Subject: Re: Q about rsize=8192,wsize=8192 for NFS expt.swe - why? ancient leftover or valid?
On 23 February 2011 00:09, Peter Grandi <[log in to unmask]> wrote:
>> Clearly never going to happen.
>
> I imagine some ":-)" after this... "Just for fun" (while waiting for disk copies and backups to happen) I have had a look at a sw area here (I tend to worry more than most about full-'fsck' and backup-restore times) and the numbers are:
<snip!>
>
> ~12m inodes, of which ~9m files (in 3m, for ~390G or around 32KB on average, but ~7.5m files are less than 8KiB. Which actually means that the 32768 as the NFS block size will rarely matter as almost always the file is smaller than the block size.
>
> Uhm this might take many hours (probably days) to 'fsck', or restore from backups. Not a nice prospect. I guess that a site would be essentially unavailable until the sw collection is back...
>
It's worse than that; for ATLAS, the software area is also mainly
redundant copies of files (in different versions of the software), and
very deep directory trees. This is why everyone is so interested in
CVMFS (we're mainly just waiting for it to be on some production
hardware at CERN...).
Sam
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