UNIX for Dummies Questions & Answers

Environment: O.S Version HP-UX B.11.31 U ia64

What is the recommended Inode free nodes?

On our server Unix Sys Admin, have setup warning email alert when % of I-node usage is above or equal at 5%.

Sample Email:

Code:

---------------------------------------------------
Subject: WARNING: i-Node Usage On dbsrvr1:/app Is At WARNING (5%) Level Auto forwarded by a Rule
     1 Filesystem          kbytes    used   avail %used  iused  ifree %iuse Mounted on
     2 /dev/appsvg/oraclelv
     3                    174063616 134244397 37971726   78% 501538 9954802    5% /app
     4 
     5 
     6 WARNING_THRESHOLD = 5%
---------------------------------------------------------------------

But checking the output of df -i and bdf -i the outputs are different:

Code:

oracle@dbsrvr1:/app $ df -i /app
/app                   (/dev/appsvg/oraclelv  ) : 10456668 total i-nodes
                                                   9946654 free i-nodes
                                                    510014 used i-nodes
                                                         4 % i-nodes used
oracle@dbsrvr1:/app $ bdf -i /app
Filesystem          kbytes    used   avail %used  iused  ifree %iuse Mounted on
/dev/appsvg/oraclelv
                   174063616 134280038 37936178   78% 510074 9945894    5% /app

We have checked for top 30 directories with more files. There is already in crontab hourly scheduled shell script to delete audit files generated on Oracle Gird and RDBMS Home.

Please advises what causes the I-Node usage as high.

I don't understand your concern. You have the ability to have ~10.5 million files in this filesystem. You have ~.5 million files in this filesystem. You can create ~10 million more files.

Your cron job deleting files is lowering the number of used i-nodes; not raising it.

Most system administrators would be concerned if only 5% of i-nodes were available (i.e., 95% used); I don't see any reason why anyone would be concerned that you had used less than 5% of a resource unless the point was to get rid of it because it is so underused.

Besides, VxFS (which I'm assuming you're using) provides on-demand dynamic inode allocation with a theoretical limit of 2 billion, so you won't be running out of inodes anytime soon.

Ask your system administrator why he sends an alert at that level.

I have been advised by our Unix System administrator that "I-Noe Usage Warning threshold of 5%" set after witnessing an issue in the past when our production batch cycle slowed down to the i-node count on this server reaching 7%.

We have a warning in place so that we can try to take action before it reaches that point again.

Would appreciate and views on how come I-node usage of 7% can impact on the Server slowness?

Server is running on HP-UX 11.31 11i v3.

This is completely backwards! Depending on file system type, there could be issues if the i-node FREE percentage dropped to 7%, but there can't possibly be a performance problem caused by having too many i-nodes free. The warning they have chosen to give is complaining when things are in GREAT shape.

When you get to 100% used on a filesystem that doesn't automatically allocate more i-nodes when you run out, you can't create any more files. This is a HUGE problem, but they won't generate a warning in this case (100% used) they are only generating a warning when everything is great. Tell them in no uncertain terms that if they want to issue a warning when there are less than 10% free i-nodes that would be great; but the way to test for that is to look for %iused values of 90% or higher; not 5% or lower!

As has already been noted here; for some filesystems (ones that allocate i-nodes when needed), this test is completely bogus. Issuing warnings when %used values are greater than 90% always makes sense; issuing warnings for %iuse values greater than 90% makes sense on some filesystem types. Issuing warnings when either of these values is less than 5% shows a complete lack of understanding what those values mean!

A wild guess under the assumption that "production batch cycle" is some sort of job that processes files.
Your sysadmin witnessed an issue when there were lots of files to process. The number of i-nodes used is a fast way to see how many files are present in a filesystem. The problem with this approach is that ALL files in that filesystem are considered, so if you have audit files there that are not processed this warning can be misleading.

As stated by others the number of i-nodes used per se is no problem when there are so many free.