Re: SPARSE files considered harmful - please revert

["Max Bowsher" <maxb at ukf dot net>]

Rolf Campbell wrote:
> Max Bowsher wrote:
>
>> 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.
>>
>>
>> I just thought I'd throw a few more numbers into the debate:
>>
>> I patched Cygwin to respond to CYGWIN=sparse / CYGWIN=nosparse
>> Then, I did a cvs co winsup:
>>
>> "Size on disc" of checked out dir, as shown in Windows properties box:
>> Sparse: 40.7MB
>> Not sparse: 43.6MB
>> OK, so sparse seems to win? But that makes no sense - backed up by noting
>> that for various individual sparse files, "Size on disc" is reporting a
size
>> which is not an integer number of clusters.
>>
>> Now, Properties of disc, look at "Used space":
>> Difference in creating sparse checkout: ~ 200MB !!!
>> Difference in creating normal checkout: ~  40MB
>>
>> Personally, I'm inclined to trust the overall disc stats more.
>>
>> I think this evidence suggests that sparse files should NOT be on by
default
>> in Cygwin.
>
> I just checked out a corporate build system, which had average file size
> much bigger.  It decreases the available disk space by 300Megs with
> non-sparce files, and 390Megs with sparce files.

Well, that's still 90MB unneccessary disk usage. Horribly inelegant, even if
not directly inconveniencing.


Max.


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