deleting file takes longer than creating it

Andrew Reid AndrewReid at eastlink.ca
Wed May 5 08:33:33 CDT 2010


John G. Heim wrote:
> I have  a Poweredge SE1435 which seems to be very slow and i noticed 
> something odd... I can create a large file with dd faster than I can delete 
> it.
> 
> # date; dd if=/dev/zero  of=zero.txt bs=1024 count=1000000; date; rm 
> zero.txt; date
> Tue May  4 16:59:21 CDT 2010
> 1000000+0 records in
> 1000000+0 records out
> 1024000000 bytes (1.0 GB) copied, 11.7291 s, 87.3 MB/s
> Tue May  4 16:59:33 CDT 2010
> Tue May  4 17:00:09 CDT 2010
> 
> It took 12 seconds to create the file and 33 seconds to rm it. Why would 
> that be?


At the risk of telling you things you already know, are you sure it 
really takes longer.

File deletion times vary with filesystem type; search for benchmarks on 
ext3, ext4 and xfs. Search for tuning guides for your specific filesystem.

But first make sure you are solving a "real" problem, try this test:

dd if=/dev/zero of=zero.txt bs=1024 count=1000000; sync; echo 3 > 
/proc/sys/vm/drop_caches ; sleep 15 ; time rm /opt/tmp/ZZ;



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