天蝎女和双鱼男配对:OTN Discussion Forums : Cannot create data st...

RajG

Posts: 11
Registered: 12/04/09 Cannot create data store shared-memory segment error
Posted: 2009-12-4 上午9:59     Reply Hi,

Here is some background information:

[ttadmin@timesten-la-p1 ~]$ ttversion
TimesTen Release 11.2.1.3.0 (64 bit Linux/x86_64) (cmttp1:53388) 2009-08-21T05:34:23Z
Instance admin: ttadmin
Instance home directory: /u01/app/ttadmin/TimesTen/cmttp1
Group owner: ttadmin
Daemon home directory: /u01/app/ttadmin/TimesTen/cmttp1/info
PL/SQL enabled.

[ttadmin@timesten-la-p1 ~]$ uname -a
Linux timesten-la-p1 2.6.18-164.6.1.el5 #1 SMP Tue Oct 27 11:28:30 EDT 2009 x86_64 x86_64 x86_64 GNU/Linux

[root@timesten-la-p1 ~]# cat /proc/sys/kernel/shmmax
68719476736

[ttadmin@timesten-la-p1 ~]$ cat /proc/meminfo
MemTotal: 148426936 kB
MemFree: 116542072 kB
Buffers: 465800 kB
Cached: 30228196 kB
SwapCached: 0 kB
Active: 5739276 kB
Inactive: 25119448 kB
HighTotal: 0 kB
HighFree: 0 kB
LowTotal: 148426936 kB
LowFree: 116542072 kB
SwapTotal: 16777208 kB
SwapFree: 16777208 kB
Dirty: 60 kB
Writeback: 0 kB
AnonPages: 164740 kB
Mapped: 39188 kB
Slab: 970548 kB
PageTables: 10428 kB
NFS_Unstable: 0 kB
Bounce: 0 kB
CommitLimit: 90990676 kB
Committed_AS: 615028 kB
VmallocTotal: 34359738367 kB
VmallocUsed: 274804 kB
VmallocChunk: 34359462519 kB
HugePages_Total: 0
HugePages_Free: 0
HugePages_Rsvd: 0
Hugepagesize: 2048 kB

extract from sys.odbc.ini

[cachealone2]
Driver=/u01/app/ttadmin/TimesTen/cmttp1/lib/libtten.so
DataStore=/u02/timesten/datastore/cachealone2/cachealone2
PermSize=14336
OracleNetServiceName=ttdev
DatabaseCharacterset=WE8ISO8859P1
ConnectionCharacterSet=WE8ISO8859P1

[ttadmin@timesten-la-p1 ~]$ grep SwapTotal /proc/meminfo
SwapTotal: 16777208 kB

Though we have around 140GB memory available and 65GB on the shmmax, we are unable to increase the PermSize to any thing more than 14GB. When I changed it to PermSize=15359, I am getting following error.

[ttadmin@timesten-la-p1 ~]$ ttIsql "DSN=cachealone2"

Copyright (c) 1996-2009, Oracle. All rights reserved.
Type ? or "help" for help, type "exit" to quit ttIsql.

connect "DSN=cachealone2";
836: Cannot create data store shared-memory segment, error 28
703: Subdaemon connect to data store failed with error TT836
The command failed.
Done.

I am not sure why this is not working, considering we have got 144GB RAM and 64GB shmmax allocated! Any help is much appreciated.

Regards,
Raj

ChrisJenkins

Posts: 2,274
Registered: 12/16/05 Re: Cannot create data store shared-memory segment error
Posted: 2009-12-4 上午10:40   in response to: RajG     Reply You have 16777208 KB of swap. This is exactly 15 GB. I suspect this is insufficient to allow allocation of a large enough shared memory segment. Try adding several more GB of swap space and then try again. Swap space should generally be at least 1.5x total physical memory size.

Chrisg_raju

Posts: 2
Registered: 10/03/99 Re: Cannot create data store shared-memory segment error
Posted: 2009-12-12 下午2:43   in response to: ChrisJenkins     Reply Hi Chris,

Thanks for the response.

I got the help of Linux admins to increase the swap space.

[ttadmin@timesten-la-p1 info]$ grep SwapTotal /proc/meminfo
SwapTotal: 155189240 kB

But I am getting following error now:

[ttadmin@timesten-la-p1 info]$ ttIsql "DSN=cachealone2"

Copyright (c) 1996-2009, Oracle. All rights reserved.
Type ? or "help" for help, type "exit" to quit ttIsql.

connect "DSN=cachealone2";
836: Cannot create data store shared-memory segment, error 28
703: Subdaemon connect to data store failed with error TT836
The command failed.
Done.

The cachealone2 entry is

[cachealone2]
Driver=/u01/app/ttadmin/TimesTen/cmttp1/lib/libtten.so
DataStore=/u02/timesten/datastore/cachealone2/cachealone2
PermSize=15300
OracleNetServiceName=ttdev
DatabaseCharacterset=WE8ISO8859P1
ConnectionCharacterSet=WE8ISO8859P1

Shmmax value is

[ttadmin@timesten-la-p1 info]$ cat /proc/sys/kernel/shmmax
68719476736

Can you please help us here?

Thanks,
Raj

ChrisJenkins

Posts: 2,274
Registered: 12/16/05 Re: Cannot create data store shared-memory segment error
Posted: 2009-12-13 上午1:22   in response to: g_raju     Reply Have you also checked the kernel parameter 'shmall'? This sets the maximum number of shared memory pages that can be allocated system wide. The default is usually fairly small. The value is specified in terms of memory pages which are uaually 4096 bytes. The minimum value for this kernel paramater should be:

SHMMAX (in bytes) / PAGE_SIZE

so for your case it should be set to at least 16777216. If anything else apart from TimesTen is using shared memory then shmall should be set even higher to take that usage into account as well.

Could you please check the current value of 'shmall' and if it is too small increase it and try again.

In any event please let us know the outcome.

Chris

RajG

Posts: 11
Registered: 12/04/09 Re: Cannot create data store shared-memory segment error
Posted: 2009-12-13 上午2:04   in response to: ChrisJenkins     Reply Hi Chris,

Thanks for yours reply.

I have checked and the values are:

[ttadmin@timesten-la-p1 ~]$ cat /etc/sysctl.conf|grep shm
kernel.shmmax = 68719476736
kernel.shmall = 4194304
[ttadmin@timesten-la-p1 ~]$ getconf PAGESIZE
4096
[ttadmin@timesten-la-p1 ~]$

Going by this, I should be atleast set PermSize as 50GB not can't increase more than 15GB.

Regards,
Raj

ChrisJenkins

Posts: 2,274
Registered: 12/16/05 Re: Cannot create data store shared-memory segment error
Posted: 2009-12-13 上午2:10   in response to: RajG Helpful   Reply With a 4096 byte pagesize and SHMALL = 4194304, total system wide shared memory is limited to 4194304 * 4096 bytes = 17179869184 bytes which = 16 GB. That's very close to the limit of what you are trying to use and there are almost certainly other things using shared memory on the machine. you need to make shmall much larger and then retry.

ChrisRajG

Posts: 11
Registered: 12/04/09 Re: Cannot create data store shared-memory segment error
Posted: 2009-12-14 上午2:21   in response to: ChrisJenkins     Reply Hi Chris,

We have increased the SHMALL to 31457280 and SHMMAX to 128849018880. I can now increase the PermSize to 117760 and it all works fine.

Thanks.

Regards,
Raj