11-29-2012 12:28 AM
Hi there,
I want to ask what's the meaning of 'blocks used for indirects', and how is it calculated.
On RHEL5.7
# /opt/VRTS/bin/fsadm -D -E /ocr1
Directory Fragmentation Report
Dirs Total Immed Immeds Dirs to Blocks to
Searched Blocks Dirs to Add Reduce Reduce
total 3 0 3 0 0 0
File System Extent Fragmentation Report
Free Space Fragmentation Index : 6
File Fragmentation Index : 4
# Files Fragmented by Fragmentation Index
0 1-25 26-50 51-75 76-100
3 1 0 0 0
Total Average Average Total
Files File Blks # Extents Free Blks
4 3768 4 1010666
blocks used for indirects: 0
% Free blocks in extents smaller than 64 blks: 0.02
% Free blocks in extents smaller than 8 blks: 0.00
% blks allocated to extents 64 blks or larger: 99.79
Free Extents By Size
1: 2 2: 2 4: 3
8: 3 16: 2 32: 3
64: 1 128: 2 256: 2
512: 2 1024: 1 2048: 0
4096: 2 8192: 2 16384: 0
32768: 0 65536: 1 131072: 1
262144: 1 524288: 1 1048576: 0
2097152: 0 4194304: 0 8388608: 0
16777216: 0 33554432: 0 67108864: 0
134217728: 0 268435456: 0 536870912: 0
1073741824: 0 2147483648: 0
Solved! Go to Solution.
11-29-2012 03:42 AM
11-29-2012 03:42 AM
11-29-2012 07:36 AM
Hi,
Mike is spot on.
In your example above, the files in the FS are not using any indirect addressing in the storage of the extents, most likely contained by indirection or direct extents
Indirect addressing is used by the FS when the files data cannot be adddressed by direct extents.
Example,
Lets say your app creates a file and does 1MB write. Most likely that 1MB of data will be stored as a single extent (offset, length). The inode for the file will address this extent directly (the inodes simply points to the location of the data on disk). Later as the file goes the varying changes, the file may need to be stored as a number extents. If it cannot be address in ten extents, then the FS will have to use an indirect address block that can address mutiple extents.
Note, it appears you are using a recent version that displays the fragmentation index, this should help in understanding the fragmentation data.
cheers
tony