Using diskkeeper for defragmenting?

Hi there

Has anyone used diskkeeper for defragmentation or does anyone know if Open-E has it built in please?

Regards
Nick

Please keep in mind that Linux file system are constructed in such a way that defragmentation is not needed ( the kernel takes care about it ).
The fragmentation is on the level of about 1-2 %. Preparing an defragmentation algorithm is possible but not needed - the gain of performance will rather not be visible

Also the DSS does not understand the underlying file system on the LUN. With DSS, the disk is carved into Logical Volumes which are served to your servers. So no tools are provided to do any defragmentation.

If you are using iSCSI, then you can defragment your volumes by the operating system that host your iSCSI volumes, for example Windows O.S. as you can use it's defragmentation tool in case you used iSCSI.

I don't know if defragmenting would actually accomplish anything.

Since iSCSI LUNs are virtual block IO devices, the seek time optimization which a defragmenter provides would be of little value, since the chance that the read/write head on the HDD devices in the SAN being at the correct position for the next IO request would be about nil.

So, the time spent by the defragmenter to group the disk blocks for access performance would simply generate a lot of SAN disk IO would have no real effect.

Further, all defragmenters work on the basis of that there is no Read cache for the virtual disk. Almost all RAID controllers provide read cache, some even provide write cache. Finally, most SAN software provide read cache functionality. So, if you have predictive read cache the benefit of defragmenting is almost nullified.