Major: NetXMS linux disk space check must know reserved blocks count
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extX partitions reserves some % of blocks (which can be freed most time, but no one does that
).I have noticed, that free space reported by NetXMS agent differs from what is seen using "df".
I see only one explanation - NetXMS check does not pay an attention to reserved block count.Detailed:
NetXMS agent ver: 0.2.27
Space check via DiskFreePerc[root@XXX ~]# df -kh
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 12G 8.7G 2.3G 80% /
...
[root@XXX ~]# tune2fs -l /dev/sda2
...
Block count: 3072431
Reserved block count: 153621
...* df shows 20% free space.
* NetXMS reports 24% for this mountpoint (I have looked a bit later +/- 1%)
* 4,99% approx reservedRepeated once again:
[root@XXX ~]# df -kh
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 12G 8.3G 2.8G 76% /
...[root@XXX ~]# df -k
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/sda2 12096756 8642080 2840192 76% /
...* df shows 76% used space.
* NetXMS shows 28% free space
* 4,99% approx reservedDifference: 4%
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Hmm.
Nope, here is somthing elseon an another machine, with almost same parameters, data differs:
NetXMS agent: 0.2.19
[root@YYY ~]# df -k
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/sda2 12096756 3191224 8291048 28% /[root@YYY ~]# df -kh
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 12G 3.1G 8.0G 28% /
...[root@YYY ~]# tune2fs -l /dev/sda2
...
Block count: 3072431
Reserved block count: 153621
...* df shows 28% used space
* NetXMS shows 73% free disk space
* 4,99% approx reservedDifference between df & NetXMS is 1% in this case. And 4% in previous case. WTF?
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There are two parameters for disk space on UNIX: Disk.Free (or Disk.FreePerc) and Disk.Avail (or Disk.AvailPerc). First shows total amount of free space, including reserved blocks. Second shows free space available to non-root users - free space without reserved blocks. You should compare Disk.Avail results with df output.
Best regards,
Victor -
There are 2 situations described:
1st with server XXX, which shows how bad is to do not read manual. Actually, I have seen Disk.Free & Disk.Avail, but didn`t udnerstand from an explanation that difference is about reserved blocks, so i throw it
:$ Sorry. Looks stupidEverything okay with this server. Checks works fine.
2nd situation is with server YYY.
I have added Disk.Avail and got 5% difference with DiskFree.
But reported data still doesn`t fit together with DF produced one.
With Disk.Avail - 1-4% misses (on different size partitions) !!![root@YYY netxms-0.2.31]# df -kh
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 12G 3.1G 7.9G 29% /
...
/dev/sda5 48G 31G 15G 69% /export/stroage0
/dev/sdb1 268G 73G 182G 29% /export/storage1While NetXMS reports free space:
/ - 68 ::: 100 - 29 = 71 : 3% missed
/export/stroage0 - 30 ::: 100 - 69 = 31 : 1% missed
/export/storage1 - 67 ::: 100 - 29 = 71 : 4% missedI did NetXMS agent ugrade from 0.2.19 to 0.2.31, but this didn`t changed situation.
Someone lies - either DF, either NetXMS.Also, seems, it is specific to server environment, because on server XXX checks works as expected.
Could it be so? -
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