nflocks
nflocks(5) - number of file locks
- References
- nflocks(5) man page
- HPUX OS: Determining nflock Usage Using lsof(8)
- Sys Adm: displaying the usage of the file lock table on HP-UX 11
- Sys Adm: displaying the number of used file lock (using q4 in a script*)
- Check /var/adm/syslog/syslog.log
- it is the application’s responsibility to write to syslog regarding inability to obtain a file lock
- for example:
Jun 24 17:13:11 usnbru25 smbd[5407]: nt_printing_init: Failed to open nt formsdatabase /var/opt/samba/locks/ntforms.tdb (No locks available)
Dec 4 10:06:15 frodo nmbd[1243]: tdb(/usr/local/samba/locks/unexpected.tdb): tdb_lock failed on list 3 ltype=2 (No locks available)
Dec 4 10:05:38 frodo qpopper[27188]: csmith at 192.168.0.152 (192.168.0.152): -ERR [SYS/TEMP] flock: ‘/var/mail/.csmith.pop’: No locks available (46)
Dec 4 10:05:38 frodo qpopper[27188]: csmith at 192.168.0.152 (192.168.0.152): -ERR [SYS/TEMP] flock: ‘/var/mail/.csmith.pop’: No locks available (46)
- Monitoring file lock usage - with Glance, with q4 script, or with lsof…
Glance shows “File Locks (nflocks)” usage in the System Tables screen. (keyboard short cut is ‘t’). To monitor usage, here’s a glance adviser script below. This script can be run periodically from cron to monitor nflocks usage over time.
- nflocks.adviser script:
print GBL_STATDATE,” “,GBL_STATTIME,” Total
nflocks: “,TBL_FILE_LOCK_AVAIL,” nflocks in-use: “,TBL_FILE_LOCK_USED - command line to run from
cron:
# glance -j 1 -iterations 1 -adviser_only
-syntax \
/home/erich/nflocks.adviser 2>/dev/null | head -1
>>/var/adm/nflocks.log
- q4 script -
#!/usr/bin/sh
/usr/contrib/bin/q4
/stand/vmunix /dev/mem <<-EOF
load struct
locklist from &locklist max nflocks
keep ll_count !=
0
EOF
(note: You may need to run
“q4pxdb
/stand/vmunix” if you get complaints
from q4)
- For example:
# ./nflocks.sh
see help topic q4live regarding use of /dev/mem
Reading kernel symbols …
Reading data types …
Initialized PA-RISC 1.1 (no buddies) address translator …
Initializing stack tracer …
Get the latest Q4 news by typing “news | more”.
loaded 200 struct locklists as an array (stopped by max count)
kept 7 of 200 struct locklist’s, discarded 193
#
- lsof - The unsupported tool called lsof can be used.
- Where to get unsupported tool called lsof: ftp://hprc.external.hp.com/lsof.README.txt
- For example:
- For a pure count of how many locks are in-use, use:
- # ./lsof | awk ‘{print $4}’| sed -n ‘/^[0-9]/p’ |sed ’s/[0-9]*//’ | awk ‘{if (length($1) > 1) print $1}’ | wc -l
- NOTE:this magic brought to you by carefull reading of the lsof(8) man pagethat explains the FD (4th field) as a file descriptor number followedby rwu, space, or “-”, and then followed by one of NrRwWuUx (see lsof(8) man page at “The HP-UX Porting and Archive Centre”:
[Canada UnitedKingdom USA Utah] for full details).
- in SD-UX format at “The HP-UX Porting and Archive Centre”:
Canada: http://hpux.ee.ualberta.ca/
United Kingdom: http://hpux.connect.org.uk/
USA: http://gatekeep.cs.utah.edu/
