IDS Forum

RE: 2 shared memory segments [18848 [18849]

Posted By: Brian Amstutz
Date: Monday, 1 February 2010, at 4:06 p.m.

In Response To: 2 shared memory segments (Brian Amstutz)

Thanks Bruce and Andy.

I have received this message both when only restarting Informix AND when
rebooting the entire server. I've used ipcs to try to find out what else
is using shared memory. I've identified a couple of apps and placed
Informix ahead of those in the startup order. However, there are some
ipcs entries whose CPID or LPID do not show up in the current list of
processes - not sure if this is "normal" under HPUX or not???

'top' nearly always shows the 3 informix cpu vp's as the top 3 process -
at least all three within the top 8 processes.

I checked the machine notes and the only kernel parameter that wasn't set
high enough was semmnu - I bumped it up from 256 to 2048 and will have to
a find time to reboot the system. The recommendation for shmmax is
anywhere from 4Gb up to the maximum allowed. Currently, ours is set to
around 286Gb and the max allowed is 4096Gb. I may not understand exactly
how shmmax is used but with only a 22Gb database, 8Gb RAM and 300Gb total
disk space - it seems like 286Gb for the max shared memory size should be
plenty large; however, I have bumped this up to approx 500Gb

Recommended SHMBASE is 0x0L - ours is set to 0x0 (minus the L) which I
*THINK* is the same thing???

Nothing of interest found in the syslogs

Brian

>-----Original Message-----
>From: ids-bounces@iiug.org [mailto:ids-bounces@iiug.org] On Behalf Of
>brucemarchu@aol.com
>Sent: Friday, January 29, 2010 8:36 PM
>To: ids@iiug.org
>Subject: Re: 2 shared memory segments [18848 [18849]
>
>Hi Brian,
>
>Here are several things to consider in addition to onconfig parameters:
>1. There might be a problem with not enough available memory due to
memor=
>y useage by applications that are running on the server. When you say
"re=
>start the server" do you mean just restarting the Informix engine, or
are=
>you rebooting the actual physical machine? If your UNIX machine has acce=
>ss to the "top" command you can run top with various flags to see what
pro=
>cesses are using the most cpu's and the related memory being used.
>2. Is the Informix engine crashing or are you doing an orderly shutdown=
>and then a restart? If the Informix engine is hanging or crashing, then=
>are you checking to make sure that all of the Informix memory segments
ha=
>ve been cleaned out before a restart. You can use ipcs and various flags=
>such as ipcs -a, and ipcs -m from the UNIX prompt.
>3. Check the Informix machine and documentation notes to see settings
for=
>various UNIX kernel parameters relating to memory, and recheck your
curre=
>nt settings. Make sure that you have at least the minimum values shown
fo=
>r memory related settings. Note that changing certain kernel parameters
mi=
>ght require a reboot of the physical machine. =20
>4. Recheck the setting for the starting memory location SHMBASE in the
onc=
>onfig file.
>5. Recheck the UNIX system logs [ maybe at /var/adm/syslog or a similar=
>location] to see if there are any error message regarding memory.
>
>Regards,
>Bruce
>
>-----Original Message-----
>From: Brian Amstutz <brian.amstutz@asburyseminary.edu>
>To: ids@iiug.org
>Sent: Fri, Jan 29, 2010 12:31 pm
>Subject: 2 shared memory segments [18848]
>
>Informix 10.00.HC5 HP-UX 11i v2=20
>Recently, I've started getting message like the following when I restart=
>=20
>he server=20
>Could not create single shared memory segment with resident and=20
>on-resident partitions. Proceeding to create 2 shared memory segments=20
>nstead.=20
>Sometimes, the server startup continues OK but other times the above=20
>essage is followed by the following or similar message:=20
>shmget: [ENOMEM][12]: key 52574802: out of shared memory, check system
max=
>=20
>hared memory segment size=20
>t_shm_init: can't create virtual segment=20
>I'm guessing it's maybe a kernel parameter (shmmax?) issue but I haven't=
>=20
>it on the correct one to increase or how much to increase it by.=20
>shmmax =3D 307200000000=20
>HMVIRTSIZE =3D 321536=20
>uffers =3D 350000 (2k)=20
>Any ideas what to tune and what to tune it to?=20
>Thanks!=20
>Brian=20
>
>*************************************************************************
*=
>****=20
>Forum Note: Use "Reply" to post a response in the discussion forum.=20
>
>
>*************************************************************************
******
> Forum Note: Use "Reply" to post a response in the discussion forum.

Messages In This Thread

• 2 shared memory segments
  Brian Amstutz -- Friday, 29 January 2010, at 3:31 p.m.
  • RE: 2 shared memory segments [18848 [18849]
    Andrew Lennard -- Monday, 1 February 2010, at 12:52 p.m.
  • RE: 2 shared memory segments [18848 [18849]
    Brian Amstutz -- Monday, 1 February 2010, at 4:06 p.m.
  • Re: 2 shared memory segments [18848 [18849] [18862
    brucemarchu@aol.com -- Tuesday, 2 February 2010, at 10:40 p.m.
  • RE: 2 shared memory segments [18848 [18849] [18862
    Brian Amstutz -- Wednesday, 3 February 2010, at 10:06 a.m.
  • RE: 2 shared memory segments [18848 [18849] [1....
    Brian Amstutz -- Friday, 5 February 2010, at 4:08 p.m.

IDS Forum is maintained by Administrator with WebBBS 5.12.