XFS Preallocation

[Jef Fox]

We are having some problems with preallocation of large files.  We have
found that we can preallocate about 500 1GB files on a volume using the
resvsp and truncate commands, but the extents are still showing up as
preallocated.  Is this a problem?  The OS appears to think the files are
allocated and correctly sized. 

 

For reference, we are trying to create files for an external piece of
equipment to write to a SSD with.  The SSD would then be mounted in RHEL
and the data pulled off in the 1G chunks.  Because of the nature of the
data, we need to constantly erase and recreate the files and
preallocation seems to be the fastest option.  We don't really care if
the data gets 0'ed out.  Is there another method - allocsp takes too
long for this application?  Or, does it matter if XFS thinks the extents
are preallocated but unwritten if no other files are written to the
disk?

 

Thanks

Jef

 

 

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