Defragmentation

Hi,
there is no defragmentation, because it isnt needed with the Celerra file system.

Celerra does not have a builtin Defragmenter.

But why do you need to defragment Celerra data?

See knowledgebase emc70573:
"FFS tries to allocate 'logically close' blocks close. For instance, it allocates (if possible) regular file inodes in the same group as the directory holding them, and data blocks for a file in the same group as the file's inode. Alternatively, it allocates directory inodes on the less loaded group, and it forces the change of cylinder group at each megabyte of file size (to avoid fragmentation inside a cylinder group). The allocation uses geometry parameters to compute a ``closest block''.

So, there is a defrag process but, basically, you don't need to defrag since the file system code is 'tuned' to discourage fragmentation. You'll likely get a low fragmentation (2-5% of the files or so), but this will remain constant except when the partition gets very full and there are lots of file creations/deletions with extremely funny file sizes. From our experience with Celerra, EMC have yet to find a customer who has needed to defrag file systems to regain access performance."

Thank you!

How about metadata defragmentation? We have a CIFS server where the content is changed on daily basis, about 20%. There are lots of read ops , about 20 hours out of 24 hours and write 12 - 15hours.

thanks,