difference between filesystem size and volume size

Hi All,

Does anybody know why size is diferent between the nas_fs -size and nas_volume -size ? Or this question does not make sense ?

# nas_fs -i file_system_name

id        = 776

name      = file_system_name

volume    = v627

auto_ext  = hwm=90%,max_size=3276800M (reached),thin=no

disks     = d89,d37,d101,d49

# nas_fs -size file_system_name

total = 3226800 avail = 947597 used = 2279203 ( 71% ) (sizes in MB) ( blockcount = 6710886400 )

volume: total = 3276800 (sizes in MB) ( blockcount = 6710886400 ) avail = 947597 used = 2329203 ( 71% )

# nas_volume -info v627

id          = 627

name        = v627

acl         = 0

in_use      = True

type        = meta

volume_set  = s164,v3998,v4000,v4016,v4026,v4030,v4032,v4034,v4038,v4108,v4134,v4142,v4212,v4214,v5097,v5101,v5105,v5123,v5474,v5476,v6176,v6404,v7444,v7648,v7650,v7656,v7681

disks       = d89,d37,d101,d49

# nas_volume -size v627

total = 3276800 avail = 0 used = 3276800 ( 100% ) (sizes in MB)

File system size shows total = 3226800 avail = 947597 used = 2279203 while nas_volume shows total = 3276800 avail = 0 used = 3276800 ( 100% ) (sizes in MB).

where is located available space reported on nas_fs -size output ? I have checked all volumes and they have nothing in availabe space. Maybe, the space is tottaly allocated to filesystem, and  nas_fs -size reads information from filesystem metadata instead of reads from volumes.

This question is just a curiosity about how the nas_fs command build the ouptut. We are investigating some problems with filesystem checkpoints and savvol utilization. We already found that the filesystem has high writes and modification which requires a lot of space on savvol to refreshes ckpts.

Thanks in advance for replies.

Marcos