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Accounting for disk space
Hi,
I'm not sure if anyone else has tried to do this - but I've been asked to work out where the disk space allocated from our Clariions to our Celerras is actually used.
I started by running nas_pool -size to get the available disk, it comes out something like this:
id = 10
name = clarata_archive
used_mb = 16432655
avail_mb = 472093
total_mb = 16904748
potential_mb = 0
I then tried adding up the space used by all the filesystems, checkpoint filesystems and the space required for replication savvols.
It looks something like this:
total space of luns from clariion 16904748
Allocated to fs 14506855
Allocated to checkpoint 396120
Allocated to replication savvol 1272003
total Used 16174978
Free 729770
As you can see the available mb figure from the nas_pool command is 472093mb but adding up all the allocated space comes to 729770mb.
I can't figure out where the extra 257677mb have gone.
My question is - should adding the space allocated to filesystems, checkpoints and replication equal the total space used - or is there something else that I've missed?
Thanks,
Sheppie
I'm not sure if anyone else has tried to do this - but I've been asked to work out where the disk space allocated from our Clariions to our Celerras is actually used.
I started by running nas_pool -size to get the available disk, it comes out something like this:
id = 10
name = clarata_archive
used_mb = 16432655
avail_mb = 472093
total_mb = 16904748
potential_mb = 0
I then tried adding up the space used by all the filesystems, checkpoint filesystems and the space required for replication savvols.
It looks something like this:
total space of luns from clariion 16904748
Allocated to fs 14506855
Allocated to checkpoint 396120
Allocated to replication savvol 1272003
total Used 16174978
Free 729770
As you can see the available mb figure from the nas_pool command is 472093mb but adding up all the allocated space comes to 729770mb.
I can't figure out where the extra 257677mb have gone.
My question is - should adding the space allocated to filesystems, checkpoints and replication equal the total space used - or is there something else that I've missed?
Thanks,
Sheppie
Rainer_EMC
6 Operator
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8645 Posts
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Posted September 19th, 2008 04:00
yes, I would use that volume total number.
Its consistent with what nas_volume shows for the underlying volume
I *guess* the difference is either metdata or alignment but will try to ask
Message was edited by:
RainerRainer_EMC
6 Operator
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8645 Posts
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Posted September 19th, 2008 09:00
you're very welcome
As I've guessed, the difference is the file system structures (superblocks, block maps, inodes), which is typically around 1.5%
Your other 30GB I guess is various little pieces like data mover and VDM root file systems or the control LUNs (2x11GB + 4x2GB)
sheppie
1 Rookie
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Posted September 19th, 2008 03:00
[nasadmin@Celerra1 nasadmin]$ nas_fs -size fs1
total = 342374 avail = 32467 used = 309907 ( 90% ) (sizes in MB) ( blockcount = 712048640 )
volume: total = 347680 (sizes in MB) ( blockcount = 712048640 )
Then I use the 342374 figure as the amount of disk space used by the filesystem. But I just noticed the other figure underneath that which is slightly higher - 347680. Should I be using that number instead?
Sheppie