FSRM reports different size than Explorer

the question is: metric windows file server resource manager using determine how of quota in use?

running w2k3 r2 storage server.  the volume in question 3tb array, partition formatted in 4k blocks.  we use directory quotas our project space management. (i.e. f:\project 1, 20gb, f:\project2 10gb, etc.)  noticed directory quota reporting different size when viewed in explorer (size on disk)   

i set couple of experiments confirm saw.

test 1 - created 100 '0' byte files
total size = 0 bytes
explorer size on disk = 0 bytes
fsrm quota = 101k in use

test 2 - create 1 hundred '1' byte files
total size = 100 bytes
explorer size on disk = 400k bytes (makes sense, via 4k block size)
fsrm quota = 101k in use

test 3 - create 1 hundred '100' byte files
total size = 9.76 k
explorer size on disk = 400k
fsrm quota = 101k in use

test 4 – since know drive formatted in 4k blocks, let's see how windows reads 1 hundred 4k files:
create 1 hundred '4000' byte files
size = 390k
explorer size on disk = 400k
fsrm quota = 501k in use

interesting.  i'm curious - where's threshold that changes quota 'in use' size 101k 501k.  by trial , error continue 'one hundred file tests' until find cut over.  long story short:

create 1 hundred '728' byte files

size = 71.0k (72,800 bytes)
explorer size on disk = 400k
fsrm quota = 101k in use

create  1 hundred '729' byte files

size = 71.1k (72,900 bytes)
explorer size on disk = 400k
fsrm quota = 501k in use

what quota manager reading determines quota in use?

btw - discrepancy discovered becasue 1 of our servers uses symantec enterprise vault - archiving service replaces older data placeholder files.  noticed though directory contained nothing these placeholder files our quota numbers didn't add up.

for example directory containing: 

7 files, original file size = 1.5gb

enterprise vault archives them, result:
7 files, explorer size on disk = 28kb ( 7 x 4kb = 28)
fsrm quota shows: 5kb of disk space in use  ??

test 2
18 files, original total file size = 8.45gb
after archiving:

size on disk = 72k (18 files)
quota shows = 60k in use

i expect the' size on disk' , 'in use' quota numbers match, not.

i know there's lot of info going on here.  guess want know if fsrm doing determine these sizes?  on small directories difference isn't signficant, on huge projects (300gb+), discrepancy between quota , size on disk significant.

thanks in advance info can provide.

 

hi,

 

i tried tests mentioned , got same result. here several explanations disk quota:

 

1. explorer count ntfs stream data while quota management count in total space usage.

 

2. quota management use file on disk size plus file record (1k). example, in folder, there 50000 1kb file, explorer report total size 48.8mb. however, quota management report 244mb (50000*5/1204).

 

3. in explorer, if current logon user not have permission on folder/files, folder/files size not counted total size in properties window of parent folder. quota management use filter driver in file system level not require file access permission , can report folder/file size.

 

they may not explain tests, sent email related development group , waiting further information. post here if reply.

 

Windows Server  >  File Services and Storage