EPERM error under heavy load on 32 user SCO ODT 3.0 System

EPERM error under heavy load on 32 user SCO ODT 3.0 System

Post by soulma » Thu, 31 Oct 1996 04:00:00



I wonder if anybody has heard about this problem.  We have a customer
set up with open desk top 3.0 (3.2.4) licensed for 32 users. We have
never ha 32 unique users on the system, but do have upwards of 55
processes that talk to serial ports connected to modems. All of these
have a database open. All of these processes are the same user ID.
( I can only assume this counts as one user) When ten additional
(individual) users login and run the forground application (which also
opens the same databases), the 10th user gets an EPERM error upon
attempting the database open. (Ctree Plus is being used for the
database) Of course the file permissions on the database file are
perfectly OK.

When someone logs out, or if we terminate one of the poll processes,
we can successfully open the database without the EPERM.  What's
going on?? this is a 32 user system. (the failure occurs suspiciously
close to the magic number 64)

Any insight would be appreciated.

thanks

scott turner

 
 
 

EPERM error under heavy load on 32 user SCO ODT 3.0 System

Post by Jean-Pierre Radl » Thu, 31 Oct 1996 04:00:00


soulmate propounded certain bytes, to wit:
|
| I wonder if anybody has heard about this problem.  We have a customer
| set up with open desk top 3.0 (3.2.4) licensed for 32 users. We have
| never ha 32 unique users on the system, but do have upwards of 55
| processes that talk to serial ports connected to modems. All of these
| have a database open. All of these processes are the same user ID.
| ( I can only assume this counts as one user) When ten additional
| (individual) users login and run the forground application (which also
| opens the same databases), the 10th user gets an EPERM error upon
| attempting the database open. (Ctree Plus is being used for the
| database) Of course the file permissions on the database file are
| perfectly OK.
|
| When someone logs out, or if we terminate one of the poll processes,
| we can successfully open the database without the EPERM.  What's
| going on?? this is a 32 user system. (the failure occurs suspiciously
| close to the magic number 64)

Slight terminological problem.  As far as your /etc/passwd file is
concerned, you could have 5 or 5000 individual user names in it.
This has nothing to do with your license, which allows 32 simultaneous
logins (under one name, or under any assortment of names).

--


 
 
 

EPERM error under heavy load on 32 user SCO ODT 3.0 System

Post by James R. Sulliva » Fri, 01 Nov 1996 04:00:00



> I wonder if anybody has heard about this problem.  We have a customer
> set up with open desk top 3.0 (3.2.4) licensed for 32 users. We have
> never ha 32 unique users on the system, but do have upwards of 55
> processes that talk to serial ports connected to modems. All of these
> have a database open. All of these processes are the same user ID.
> ( I can only assume this counts as one user) When ten additional
> (individual) users login and run the forground application (which also
> opens the same databases), the 10th user gets an EPERM error upon
> attempting the database open. (Ctree Plus is being used for the
> database) Of course the file permissions on the database file are
> perfectly OK.

> When someone logs out, or if we terminate one of the poll processes,
> we can successfully open the database without the EPERM.  What's
> going on?? this is a 32 user system. (the failure occurs suspiciously
> close to the magic number 64)

Check the value of MAXUP, which limits the number of processes a UID
can have.  Note that the restriction is not based on logins or terminals,
but on UIDs, so that in your configuration, with multiple logins (and
even though they are using the same username to log in, they are multiple
users, not a single user), all using the same UID, you could be hitting
up against that limit.

The other thing to check is NOFILES, which limits the number of files a
process can have open.  Perhaps the database engine in bumping against
that ceiling and cause the EPERM error.

--

----
Jim Sullivan            "Don't plant your bad days.  They grow into bad
SMB Segment Marketing    weeks and then bad months and before you know it

416 216 4611

 
 
 

EPERM error under heavy load on 32 user SCO ODT 3.0 System

Post by soulma » Sat, 02 Nov 1996 04:00:00


OK I found the problem... The application is using ctree 4.3... which
has a built in - hard-coded limit of 64 opens on any one database
in this release. It had nothing to do with tuning parameters. In that
version they locked a one byte reigion in a 64 byte fixed table in the
file header. The code attempted a lock on each successive
byte in this region of the file header... if the loop maxed out
without a lock being obtained, the 'user' limit was exceeded and
ctree returned an error code 12 (FNOP_ERR) but the errno
was 13 [EACCS] beacuse of the lock fail.

Thanks to those who responded. I appreciate the response.
Hope I can be of service in return sometime

scott

 
 
 

1. Q: lp commands do not work for normal user on SCO ODT 3.0 - why??

I'd advise you check the permissions of your lp command. For a system
not running remote line printing, 'lp' should read

        ---x--s--x 2 bin lp     580088 Dec 14 12:03 /usr/bin/lp
              ^
              |
        The uid bit allows users other than root to print.

If rlp is installed the local 'lp' command should read

        ---x--x--x 1 root other 584443 Dec 14 12:03 /usr/lpd/remote/lp

Hope this helps

      Disclaimer: These are my thoughts and may be in beta, etc

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