[Samba] samba4 ldap high load and port queue overflow
Yuriy Tabolin
tabolin at speechpro.com
Tue Nov 24 14:48:49 UTC 2015
Thanks for answer. I am very sad to see that.
I had examined samba behavior with tracer and had seen too many poll,
fcntl and stat system calls by samba task[ldapsrv] process
Elapsed Times for PID 1423,
SYSCALL TIME (ns)
dup 2653
flock 5811
lseek 33513
geteuid 42747
getpid 63819
getpeername 85480
getsockname 151683
socket 237632
accept 311871
fstat 404420
madvise 452120
readv 601524
mmap 858391
writev 910337
gettimeofday 929595
read 1064811
close 1270401
open 1733182
lstat 1938394
bind 1939462
unlink 2074873
munmap 2569299
mkdir 3539965
clock_gettime 5662586
stat 7543724
fcntl 74322331
poll 5393911015
I think may be samba something doing not optimal way. Like this, first
we try to create directory (mkdir), then we check it (stat). May be that
leads to impact filesystems and samba ldap works slower than openldap.
fcntl(15,F_SETLKW,0x7fffffffd118) = 0 (0x0)
fcntl(15,F_SETLKW,0x7fffffffd188) = 0 (0x0)
clock_gettime(13,{1448375653.000000000 }) = 0 (0x0)
mkdir("/var/db/samba4/private/sam.ldb.d",0700) ERR#17 'File exists'
stat("/var/db/samba4/private/sam.ldb.d/DC=DOMAINDNSZONES,DC=SPEECHPRO,DC=COM.ldb",{
mode=-rw------- ,inode=242034,size=4247552,blksize=32768 }) = 0 (0x0)
fcntl(16,F_SETLKW,0x7fffffffd098) = 0 (0x0)
fcntl(16,F_SETLKW,0x7fffffffd138) = 0 (0x0)
fcntl(16,F_SETLKW,0x7fffffffd098) = 0 (0x0)
fcntl(16,F_SETLKW,0x7fffffffd138) = 0 (0x0)
fcntl(16,F_SETLKW,0x7fffffffd098) = 0 (0x0)
fcntl(16,F_SETLKW,0x7fffffffd138) = 0 (0x0)
clock_gettime(13,{1448375653.000000000 }) = 0 (0x0)
clock_gettime(13,{1448375653.000000000 }) = 0 (0x0)
fcntl(16,F_SETLK,0x7fffffffd098) = 0 (0x0)
fcntl(16,F_SETLKW,0x7fffffffd118) = 0 (0x0)
fcntl(16,F_SETLKW,0x7fffffffd188) = 0 (0x0)
clock_gettime(13,{1448375653.000000000 }) = 0 (0x0)
mkdir("/var/db/samba4/private/sam.ldb.d",0700) ERR#17 'File exists'
stat("/var/db/samba4/private/sam.ldb.d/DC=FORESTDNSZONES,DC=SPEECHPRO,DC=COM.ldb",{
mode=-rw------- ,inode=242035,size=4247552,blksize=32768 }) = 0 (0x0)
fcntl(17,F_SETLKW,0x7fffffffd098) = 0 (0x0)
fcntl(17,F_SETLKW,0x7fffffffd138) = 0 (0x0)
fcntl(17,F_SETLKW,0x7fffffffd098)
23.11.2015 18:44, mathias dufresne пишет:
> Hi,
>
> I feel like I must reply off-list: Samba 4 is not yet able to use threads.
> To work around that we are about to deploy our DCs as virtual
> machines, to be able to multiply the number of Samba running.
>
> I expect you would have already thought about that, but in case you
> didn't, I said it :p
>
> I will follow closely that topic you opened. Sorry to not help more.
>
> Cheers,
>
> mathias
>
>
>
> 2015-11-23 14:50 GMT+01:00 Yuriy Tabolin <tabolin at speechpro.com
> <mailto:tabolin at speechpro.com>>:
>
> Hi all.
> I have samba 4.2.3 on freebsd 10.1 server. There are three DC and
> about 350 PC on domain. DCs have 3 CPU and 3GB RAM. Some servers
> with services like apache, exim, dovecot, etc use samba4 ldap
> (port 389) for user authentication. Some times ago after adding
> some services to use ldap I found, that samba4 cannot serve all
> ldap requests. Every 10-30 minutes I see in DCs logs:
> dc1 kernel: sonewconn: pcb 0xfffff800753d6ab8: Listen queue
> overflow: 16 already in queue awaiting acceptance (28 occurrences)
>
> After that I have used tcpdump for recording ldap-traffic and have
> seen that after TCP handshaking, server some times suddenly send
> TCP-RST to close connection. I have enlarged DCs resources (CPU
> and RAM), kern.ipc.somaxconn, did some other system tuning but
> all that didn't help. Load average on DCs permanently near 0.9-1.0
> and samba cannot serve all ldap conncetions. ldap clients works
> well because they use as minimum as two domain controllers as ldap
> servers. Is there a some performance problem in samba4, slow
> processing ldap requests or something else?
> Thanks for any help.
>
> --
> With best regards,
>
> Tabolin Yuriy
> System administrator
> Speech Technology Center
>
>
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>
--
With best regards,
Tabolin Yuriy
System administrator
Speech Technology Center
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