The df utility incorrectly suggests available space is higher than actual available space on type VxFS

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Article ID: 100024516

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Cause

Under vxfs free blocks is calculate as the sum of actual free blocks + "delayed free blocks".  Delayed free blocks whose count is increased as soon as the file gets removed but these blocks get freed up on disk only when the transaction gets done. New metadata gets flushed to the disk. Hence the discrepancy.

Resolution

The fix is to update the “deleted” free block count only after the metadata update gets flushed to disk and not before. This fix will be included in 5.1SP1RP1HF4 for SLES10 and SLES11

sles10_x86_64:
# rpm -U VRTSvxfs-5.1.101.004-RP1HF4_SLES10.x86_64.rpm
sles11_x86_64:
# rpm -U VRTSvxfs-5.1.101.004-RP1HF4_SLES11.x86_64.rpm


Issue/Introduction

The df(1M) utility reports incorrect "used" and "available" i.e., ~1.1G and ~8.9G values via statfs() on a f_type 0xa501fcf5 (VxFS) verses the du(1M) utility which suggests used space is almost depleted at ~9.85G: # df -t vxfs -h /usr/sap/LXI
Filesystem            Size  Used Avail Use% Mounted on
/dev/vx/dsk/dgilxici10ci01/lvsapLXI
                       10G  1.1G  8.9G  11% /usr/sap/LXI # du -k /usr/sap/LXI
10330904        /usr/sap/LXI
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