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Re: SPARSE files considered harmful - please revert
>>>>> "Max" == Max Bowsher <firstname.lastname@example.org> writes:
Max> Martin Buchholz wrote:
>> As a result, a non-empty but small sparse file takes up a minimum of
>> 16*clustersize bytes on the disk. My measurements suggest an overhead
>> of 32kb per file with a cluster size of 4kb.
Max> I just thought I'd throw a few more numbers into the debate:
Max> I patched Cygwin to respond to CYGWIN=sparse / CYGWIN=nosparse
Max> Then, I did a cvs co winsup:
Max> "Size on disc" of checked out dir, as shown in Windows properties box:
Max> Sparse: 40.7MB
Max> Not sparse: 43.6MB
Max> OK, so sparse seems to win? But that makes no sense - backed up by noting
Max> that for various individual sparse files, "Size on disc" is reporting a size
Max> which is not an integer number of clusters.
Max> Now, Properties of disc, look at "Used space":
Max> Difference in creating sparse checkout: ~ 200MB !!!
Max> Difference in creating normal checkout: ~ 40MB
This 5-fold expansion is just like what I saw.
Max> Personally, I'm inclined to trust the overall disc stats more.
The thing that matters is, what happens when the disk gets to 100%?
This did happen to me. I do not recall getting any "disk full" error
messages, but the disk was unhappy nevertheless. Processes writing to
the disk would tend to hang.
Max> I think this evidence suggests that sparse files should NOT be on by default
Max> in Cygwin.
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