max open files reached

Jack L. Stone jackstone at
Wed Jun 4 07:30:47 PDT 2003

At 03:29 PM 6.4.2003 +0200, Roman Neuhauser wrote:
>I have a script run by periodic(8) in the daily batch that is supposed
>to backup all databases from the local MySQL server using
>mysqlhostcopy(1). It used to run fine for a few months, but has
>been failing consistently with ENFILE (23) lately.
>The box is an Intel Celeron 533 (or some such) with 128 MB RAM. These
>are all the related sysctl knobs I could find. This is as of 20:40, so
>the value of kern.openfiles is reasonable.
>roman at ishtar ~ 1001:0 > sysctl -a kern|grep files
>kern.maxfiles: 2024
>kern.maxfilesperproc: 1821
>kern.openfiles: 512
>I've cranked the kern.maxfiles value to 4096, and the backup has run to
>completion again, but am I risking anything? I mean, the fd's cost
>memory, is there any potential for problems?

I don't see any problems with raising to 4096 as 2024 looks awful low. Most
of mine run 12000+ and the lowest at about 8000. I do have more CPU and RAM
in the equation. What do you have the "maxusers" set to in your kernel? I
have found this will usually take care of making the correct calculations
for the max files. A setting of "0" is good for later versions of FBSD.
Don't remember what version changed this & you didn't mention your version.

Otherwise, you'll need to set the max files in your /boot/loader.conf so
they stay up at the 4096, or whatever workable level is good for you.

Best regards,
Jack L. Stone,

SageOne Net
jackstone at

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