[Samba] high cpu load

Wayne Cochran wcochran at vancouver.wsu.edu
Thu Oct 23 21:27:27 GMT 2008 

I think I have narrowed down the problem why smbd processes are soaking
up so much CPU on our file server. Here are some selected samples from
strace output as I attached to the offending smbd process:

Culprit #1

I took three sample snapshots, each lasted for several seconds, and I  
took them
minutes apart from each other.  I noticed many lines involved stat'ing  
the
a single file in the 'My Documents' subdirectory:

stat64("My Documents/The Picture of Dorian Grey.rtf", {st_mode=S_IFREG| 
0744, st_size=0, ...}) = 0
utimes("My Documents/The Picture of Dorian Grey.rtf", {1224548572, 0})  
= 0

To see the frequency of these I grep'ed and use wc -l to get a line  
count:

# grep 'stat64("My Documents/The Picture of Dorian Grey.rtf"' /tmp/ 
qqq.txt | wc -l
462
# grep 'stat64("My Documents/The Picture of Dorian Grey.rtf"' /tmp/ 
rrr.txt | wc -l
1065
s# grep 'stat64("My Documents/The Picture of Dorian Grey.rtf"' /tmp/ 
ppp.txt | wc -l
429

Thousands of times this file is being stat'ed!?!?

Culprit #2 : some small samples from strace:

read(5, "\0\0\0H", 4)                   = 4
read(5,  
"\377SMB2\0\0\0\0\30\7\310\0\0\0\0\0\0\0\0\0\0\0\0\4\0\230"..., 72) = 72
stat64(".windows_settings/Application Data/SolidWorks 2008/Scheduler_2/ 
swbo1.mdb", {st_mode=S_IFREG|0744, st_size=974848, ...}) = 0
fcntl64(13, F_SETLKW64, {type=F_RDLCK, whence=SEEK_SET, start=25416,  
len=1}, 0xbfa355d4) = 0
fcntl64(13, F_SETLKW64, {type=F_UNLCK, whence=SEEK_SET, start=25416,  
len=1}, 0xbfa355f4) = 0
write(5, "\0\0\0d\377SMB2\0\0\0\0\210A\310\0\0\0\0\0\0\0\0\0\0\0"...,  
104) = 104
gettimeofday({1224788202, 767660}, NULL) = 0
select(30, [5 21 29], [], NULL, {60, 0}) = 1 (in [5], left {60, 0})
read(5, "\0\0\0)", 4)                   = 4

tat64("My Documents", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
fcntl64(13, F_SETLKW64, {type=F_RDLCK, whence=SEEK_SET, start=17928,  
len=1}, 0xbfa355d4) = 0
fcntl64(13, F_SETLKW64, {type=F_UNLCK, whence=SEEK_SET, start=17928,  
len=1}, 0xbfa355f4) = 0
write(5, "\0\0\0d\377SMB2\0\0\0\0\210A\310\0\0\0\0\0\0\0\0\0\0\0"...,  
104) = 104
gettimeofday({1224788207, 113052}, NULL) = 0
select(30, [5 21 29], [], NULL, {60, 0}) = 1 (in [5], left {60, 0})
read(5, "\0\0\0f", 4)                   = 4
read(5, "\377SMB2\0\0\0\0\30\7\310\0\0\0\0\0\0\0\0\0\0\0\0\4\0L"...,  
102) = 102
stat64("My Documents", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
fcntl64(13, F_SETLKW64, {type=F_RDLCK, whence=SEEK_SET, start=17928,  
len=1}, 0xbfa355d4) = 0
fcntl64(13, F_SETLKW64, {type=F_UNLCK, whence=SEEK_SET, start=17928,  
len=1}, 0xbfa355f4) = 0
write(5, "\0\0\0t\377SMB2\0\0\0\0\210A\310\0\0\0\0\0\0\0\0\0\0\0"...,  
120) = 120
gettimeofday({1224788207, 117652}, NULL) = 0
select(30, [5 21 29], [], NULL, {60, 0}) = 1 (in [5], left {60, 0})
read(5, "\0\0\0p", 4)                   = 4
read(5, "\377SMB\242\0\0\0\0\30\7\310\0\0\0\0\0\0\0\0\0\0\0\0\4"...,  
112) = 112
stat64("My Documents", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
gettimeofday({1224788207, 120639}, NULL) = 0
fcntl64(13, F_SETLKW64, {type=F_WRLCK, whence=SEEK_SET, start=17928,  
len=1}, 0xbfa35ba4) = 0
fcntl64(13, F_SETLKW64, {type=F_UNLCK, whence=SEEK_SET, start=17928,  
len=1}, 0xbfa35b34) = 0
stat64("My Documents", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
gettimeofday({1224788207, 122416}, NULL) = 0

Why is "My Documents" being stat'ed and read so much!?!?!

Lets see what's in this directory:

# pwd
/home/yongffa/My Documents


Almost a gigabyte of stuff?

# ls -l
total 29380
drwxr-xr-x 2 yongffa Domain Users     4096 2008-06-11 15:05 네이트 
온 받은 파일
-rwxr--r-- 1 yongffa Domain Users  3259699 2008-08-14 17:16  
ALZip_eng_632.exe
drwxr-xr-x 2 yongffa Domain Users     4096 2008-01-29 11:38 ansys
drwxr-xr-x 2 yongffa Domain Users     4096 2008-09-29 21:45 conver3k
-rwxr--r-- 1 yongffa Domain Users   109977 2008-09-29 21:45 conver3k.zip
-rwxr--r-- 1 yongffa Domain Users     1658 2008-03-27 16:39 Default.rdp
-rwxr--r-- 1 yongffa Domain Users       78 2008-10-21 10:47 desktop.ini
drwxr-xr-x 3 yongffa Domain Users     4096 2008-04-15 20:06  
fesafe.version.5.3
-rwxr--r-- 1 yongffa Domain Users   824519 2008-09-29 21:35  
free_converter_setup.exe
-rwxr--r-- 1 yongffa Domain Users    32768 2008-06-25 12:31  
helium.vancouver.wsu.edu-00000001.pst
drwxr-xr-x 2 yongffa Domain Users     4096 2008-10-14 18:26 MATLAB
drwxr-xr-x 2 yongffa Domain Users     4096 2008-10-21 10:48 My Music
drwxr-xr-x 3 yongffa Domain Users     4096 2008-10-21 10:48 My Pictures
drwxr-xr-x 2 yongffa Domain Users     4096 2008-06-25 12:46 My Videos
drwxr-xr-x 2 yongffa Domain Users     4096 2008-04-25 17:54  
Our.Finest.Hour.2008.DVDRip.x264.AC3.iNT-DG
-rwxr--r-- 1 yongffa Domain Users    32768 2008-08-04 16:29 outlook.pst
-rwxr--r-- 1 yongffa Domain Users 25739264 2008-06-28 06:01 Personal  
Folders(1).pst
root at queenbee:/home/yongffa/My Documents# du -sk .
971504	.


# ls -lR | more
total 29380
drwxr-xr-x 2 yongffa Domain Users     4096 2008-06-11 15:05 네이트 
온 받은 파일
-rwxr--r-- 1 yongffa Domain Users  3259699 2008-08-14 17:16  
ALZip_eng_632.exe
drwxr-xr-x 2 yongffa Domain Users     4096 2008-01-29 11:38 ansys
drwxr-xr-x 2 yongffa Domain Users     4096 2008-09-29 21:45 conver3k
-rwxr--r-- 1 yongffa Domain Users   109977 2008-09-29 21:45 conver3k.zip
-rwxr--r-- 1 yongffa Domain Users     1658 2008-03-27 16:39 Default.rdp
-rwxr--r-- 1 yongffa Domain Users       78 2008-10-21 10:47 desktop.ini
drwxr-xr-x 3 yongffa Domain Users     4096 2008-04-15 20:06  
fesafe.version.5.3
-rwxr--r-- 1 yongffa Domain Users   824519 2008-09-29 21:35  
free_converter_setup.exe
-rwxr--r-- 1 yongffa Domain Users    32768 2008-06-25 12:31  
helium.vancouver.wsu.edu-00000001.pst
drwxr-xr-x 2 yongffa Domain Users     4096 2008-10-14 18:26 MATLAB
drwxr-xr-x 2 yongffa Domain Users     4096 2008-10-21 10:48 My Music
drwxr-xr-x 3 yongffa Domain Users     4096 2008-10-21 10:48 My Pictures
drwxr-xr-x 2 yongffa Domain Users     4096 2008-06-25 12:46 My Videos
drwxr-xr-x 2 yongffa Domain Users     4096 2008-04-25 17:54  
Our.Finest.Hour.2008.DVDRip.x264.AC3.iNT-DG
-rwxr--r-- 1 yongffa Domain Users    32768 2008-08-04 16:29 outlook.pst
-rwxr--r-- 1 yongffa Domain Users 25739264 2008-06-28 06:01 Personal  
Folders(1).pst

./네이트온 받은 파일:
total 848532
-rwxr--r-- 1 yongffa Domain Users   5035651 2008-01-31 15:05  
loding206mpa-relaxation-ellipse-crack-1mm-06mm-Al2024-0114.inp
-rwxr--r-- 1 yongffa Domain Users 862866940 2008-01-31 14:08  
relaxation-ellipse-Al2024-comp-bogang-bojo.odb
-rwxr--r-- 1 yongffa Domain Users    125952 2008-01-31 16:25 SsCx- 
ellipse-1mm-06mm-al2024-jan23.xls

./ansys:
total 4
-rwxr--r-- 1 yongffa Domain Users 818 2008-01-29 11:38 STATUS.lis
<snip>

Is this always being read every friggin' time they log in!?!?!

Any ideas on what is going on here!?!?

--w
Wayne O. Cochran
Clinical Assistant Professor, Computer Science
Washington State University Vancouver
wcochran at vancouver.wsu.edu
http://ezekiel.vancouver.wsu.edu/~wayne

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