High APC Fragmentation

S

semprot

Well-Known Member
#1
#1
Hi,

I use 2-cpu license litespeed.
I use apc and i have uploaded apc.php.
my apc.ttl is 0.
But apc.php shows very high fragmentation every time i refresh apc.php (my site is busy site), it can reach up to 50%.
what should i do?

Code: 
apc.cache_by_default	1
apc.canonicalize	1
apc.coredump_unmap	0
apc.enable_cli	1
apc.enabled	1
apc.file_md5	0
apc.file_update_protection	2
apc.filters	
apc.gc_ttl	3600
apc.include_once_override	0
apc.lazy_classes	0
apc.lazy_functions	0
apc.max_file_size	20M
apc.mmap_file_mask	
apc.num_files_hint	1000
apc.preload_path	
apc.report_autofilter	0
apc.rfc1867	0
apc.rfc1867_freq	0
apc.rfc1867_name	APC_UPLOAD_PROGRESS
apc.rfc1867_prefix	upload_
apc.rfc1867_ttl	3600
apc.serializer	default
apc.shm_segments	1
apc.shm_size	256M
apc.slam_defense	1
apc.stat	1
apc.stat_ctime	0
apc.ttl	0
apc.use_request_time	1
apc.user_entries_hint	4096
apc.user_ttl	7200
apc.write_lock	1
 

Attachments

S

semprot

Well-Known Member
#3
#3
webizen said:
try increase apc.shm_size (=> 512M)

also apc.stat=0
Click to expand...
thanks, apc.stat is 0 now, but once i changed apc.shm_size to 512m, i started getting 503 error on all domains on my server.

Eventhough i have enough free ram (i think)
Code: 
root@mybox [/home/xxxxx]# free -m
total used free shared buffers cached
Mem: 12001 7501 4500 0 1229 3169
-/+ buffers/cache: 3102 8899
Swap: 2047 0 2047
Once i reverted it back to 256m, the 503 error gone. Do you think i need to upgrade my RAM although i have "enough" (IMO) ram?
 
Last edited:
S

semprot

Well-Known Member
#6
#6
After the litespeed was rebuilt recently, i started getting random 503 errors (not always as old situation) -- even with less traffic.
even though memory soft & hard limit have been set to 1024mb.

APC settings are still the same, at least :
- shm_size is 512mb
- ttl is 0
- stat is 0

Probably some other old litespeed settings were gone?
Is there any other settings other than memory soft & hard limit that i should check?
 
Last edited:
eva2000

eva2000

Well-Known Member
#9
#9
semprot said:
After the litespeed was rebuilt recently, i started getting random 503 errors (not always as old situation) -- even with less traffic.
even though memory soft & hard limit have been set to 1024mb.

APC settings are still the same, at least :
- shm_size is 512mb
- ttl is 0
- stat is 0

Probably some other old litespeed settings were gone?
Is there any other settings other than memory soft & hard limit that i should check?
Click to expand...
why set ttl = 0 your memory usage will keep increasing, usually for APC i have something like

Code: 
apc.ttl=7200
apc.user_ttl=3600
apc.gc_ttl = 600
never had any problems with Litespeed and LSPHP + APC

Of course make sure you aren't using LSPHP with phpSuExec for opcode cache use. I have a mysqlmymonlite.sh script to check for that http://mysqlmymon.com/#litespeedstats

Code: 
phpSuExec = 0
Code: 
------------------------------------------------
Litespeed Server & LSAPI PHP Info:
------------------------------------------------
Litespeed web server version: 4.1.12
WHM / Cpanel version: 11.32.2.25

LSPHP phpSuExec status: 
  < phpSuExec >0
  < phpSuExecMaxConn >20

WHM's PHP Handler config:
/usr/local/cpanel/bin/rebuild_phpconf --current

Available handlers: dso cgi none
DEFAULT PHP: 5
PHP4 SAPI: none
PHP5 SAPI: dso
SUEXEC: enabled
RUID2: not installed

PHP 5.3.10 (litespeed) (built: Feb  7 2012 03:02:29)
Copyright (c) 1997-2004 The PHP Group
Zend Engine v2.3.0, Copyright (c) 1998-2012 Zend Technologies
 
S

semprot

Well-Known Member
#10
#10
eva2000 said:
why set ttl = 0 your memory usage will keep increasing, usually for APC i have something like

Code: 
apc.ttl=7200
apc.user_ttl=3600
apc.gc_ttl = 600
never had any problems with Litespeed and LSPHP + APC

Of course make sure you aren't using LSPHP with phpSuExec for opcode cache use. I have a mysqlmymonlite.sh script to check for that http://mysqlmymon.com/#litespeedstats

Code: 
phpSuExec = 0
Code: 
------------------------------------------------
Litespeed Server & LSAPI PHP Info:
------------------------------------------------
Litespeed web server version: 4.1.12
WHM / Cpanel version: 11.32.2.25

LSPHP phpSuExec status: 
  < phpSuExec >0
  < phpSuExecMaxConn >20

WHM's PHP Handler config:
/usr/local/cpanel/bin/rebuild_phpconf --current

Available handlers: dso cgi none
DEFAULT PHP: 5
PHP4 SAPI: none
PHP5 SAPI: dso
SUEXEC: enabled
RUID2: not installed

PHP 5.3.10 (litespeed) (built: Feb  7 2012 03:02:29)
Copyright (c) 1997-2004 The PHP Group
Zend Engine v2.3.0, Copyright (c) 1998-2012 Zend Technologies
Click to expand...
Actually before i set ttl to 0, my fragmentation is very very high. And i read solution to set ttl to 0. And it is fine.
However after everything is fine, i rebuild the php & litespeed for some reason.
Now everything is screwed, apc wont work properly.

I asked on stackoverflow but still no solution.

http://stackoverflow.com/questions/10352458/apc-apc-fetch-returns-false-often-but-sometimes-success
 
N

NiteWave

Administrator
#11
#11
I read the post on stackoverflow, some valuable info there.
-- Compiling the APC module with --disable-apc-mmap (Disable mmap support and use IPC shm instead) should fix the issue.
-- i use SuPHP, not FastCGI
-- my hosting said he is unable to enable fastcgi on litespeed. what if i still use suphp?

when you use SuPHP under apache, and converting apache to litespeed, php will run in suExec mode. in this mode, only eAccelerator works well, APC or XCache won't work well. and in memory variable won't be shared at all between lsphp processes. in php suExec mode, lsphp process start/stop frequently. once a process stops, all in memory variables associated with the process will vanish as well. so use memcache or even disk file is the right way to keep variable value between lsphp process.
 
S

semprot

Well-Known Member
#12
#12
NiteWave said:
I read the post on stackoverflow, some valuable info there.
-- Compiling the APC module with --disable-apc-mmap (Disable mmap support and use IPC shm instead) should fix the issue.
-- i use SuPHP, not FastCGI
-- my hosting said he is unable to enable fastcgi on litespeed. what if i still use suphp?

when you use SuPHP under apache, and converting apache to litespeed, php will run in suExec mode. in this mode, only eAccelerator works well, APC or XCache won't work well. and in memory variable won't be shared at all between lsphp processes. in php suExec mode, lsphp process start/stop frequently. once a process stops, all in memory variables associated with the process will vanish as well. so use memcache or even disk file is the right way to keep variable value between lsphp process.
Click to expand...
Thank you your explanation helps me a lot. At this moment i need opcode cache, so i think i will use eaccelerator.
 
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