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Kernel UEK 2 on Oracle Linux 6.2 fixed lab server memory loss

Submitted by martin.bach on Wed, 2012-06-13 12:10

A few days ago I wrote about my new lab server and the misfortune with kernel UEK (aka 2.6.32 + backports). It simply wouldn’t recognise the memory in the server:

# free -m
             total       used       free     shared    buffers     cached
Mem:          3385        426       2958          0          9        233
-/+ buffers/cache:        184       3200
Swap:          511          0        511

Ouch. Today I gave it another go, especially since my new M4 SSD has arrived. My first idea was to upgrade to UEK2. And indeed, following the instructions on Wim Coekaerts’s blog (see references), it worked:

[root@ol62 ~]# uname -a
Linux ol62.localdomain 2.6.39-100.7.1.el6uek.x86_64 #1 SMP Wed May 16 04:04:37 EDT 2012 x86_64 x86_64 x86_64 GNU/Linux
[root@ol62 ~]# free -m
             total       used       free     shared    buffers     cached
Mem:         32221        495      31725          0          5         34
-/+ buffers/cache:        456      31764
Swap:          511          0        511

Note the 2.6.39-100.7.1! It’s actually past that and version 3.x, but to preserve compatibility with a lot of software parsing the kernel revision number in 3 tuples Oracle decided to stick with 2.6.39. But then the big distributions don’t really follow the mainstream kernel numbers anyway.

Now if anyone could tell me if UEK2 is out of beta? I know it’s not supported for the database yet, but it’s a cool kernel release and I can finally play around with the “perf” utility Kevin Closson and Frits Hoogland have mentioned so much about recently.

This here is a lot more like it:

top - 13:57:56 up  1:14,  5 users,  load average: 0.22, 0.55, 0.96
Tasks: 240 total,   2 running, 238 sleeping,   0 stopped,   0 zombie
Cpu0  : 31.8%us,  5.3%sy,  0.0%ni, 62.3%id,  0.3%wa,  0.0%hi,  0.3%si,  0.0%st
Cpu1  :  1.8%us,  0.6%sy,  0.0%ni, 97.6%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu2  :  0.0%us,  0.3%sy,  0.0%ni, 99.7%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu3  :  6.7%us,  4.8%sy,  0.0%ni, 88.5%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu4  :  0.6%us,  0.0%sy,  0.0%ni, 99.4%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu5  :  0.0%us,  0.0%sy,  0.0%ni,100.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu6  :  2.8%us,  2.0%sy,  0.0%ni, 95.3%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu7  :  0.3%us,  0.3%sy,  0.0%ni, 99.0%id,  0.3%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu8  :  0.4%us,  0.0%sy,  0.0%ni, 99.6%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu9  :  3.3%us,  6.0%sy,  0.0%ni, 90.7%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu10 :  0.3%us,  0.7%sy,  0.0%ni, 99.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu11 :  0.5%us,  0.5%sy,  0.0%ni, 99.1%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu12 : 14.7%us,  1.5%sy,  0.0%ni, 83.7%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu13 :  0.0%us,  0.0%sy,  0.0%ni,100.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu14 :  0.0%us,  0.0%sy,  0.0%ni,100.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu15 :  3.9%us,  5.7%sy,  0.0%ni, 90.3%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu16 :  0.0%us,  0.0%sy,  0.0%ni,100.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu17 :  0.0%us,  0.0%sy,  0.0%ni,100.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu18 :  2.7%us,  1.6%sy,  0.0%ni, 95.7%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu19 :  1.7%us,  0.7%sy,  0.0%ni, 97.7%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu20 :  0.0%us,  0.2%sy,  0.0%ni, 99.8%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu21 :  6.3%us,  4.4%sy,  0.0%ni, 89.3%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu22 :  0.0%us,  0.0%sy,  0.0%ni,100.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu23 :  3.9%us,  0.4%sy,  0.0%ni, 95.7%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:  32994384k total, 17078956k used, 15915428k free,   115172k buffers
Swap:   524284k total,        0k used,   524284k free, 14839688k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
14908 oracle    20   0 10.2g 113m 106m S 29.6  0.4   0:00.89 oracleorcl (DESCRIPTION=(LOCAL=YES)(ADDRESS=(PROTOCOL=beq)))
...

And whilst I’m on it-here is the output from collectl during the database creation for a SLOB run on my SSD (sda). It created the 4GB online redo logs at the time.

### RECORD   35 >>> ol62 <<< (1339593441.001)  ###

# SINGLE CPU[HYPER] STATISTICS
#   Cpu  User Nice  Sys Wait IRQ  Soft Steal Idle
      0     0    0    0    0    0    0     0  100
      1     0    0    0    0    0    0     0  100
      2     0    0    0    0    0    0     0  100
      3     0    0    0    0    0    0     0    0
      4     0    0    0    0    0    0     0    0
      5     0    0    0    0    0    0     0    0
      6     0    0    0    0    0    0     0   98
      7     0    0    0    0    0    0     0    0
      8     0    0    0    0    0    0     0  100
      9     0    0    0    0    0    0     0    0
     10     0    0    0    0    0    0     0    0
     11     0    0    0    0    0    0     0    0
     12     0    0    1    0    0    0     0   99
     13     3    0    3    0    0    0     0   92
     14     0    0    0    0    0    0     0  100
     15     0    0    0    0    0    0     0  100
     16     0    0    0    0    0    0     0  100
     17     0    0    0    0    0    0     0    0
     18     0    0    0    0    0    0     0    0
     19     0    0    0    0    0    0     0    0
     20     0    0    0    0    0    0     0    0
     21     0    0    0    0    0    0     0  100
     22     0    0    0    0    0    0     0    0
     23     0    0    0    0    0    0     0    0

# DISK STATISTICS (/sec)
#           Pct
#Name       KBytes Merged  IOs Size  KBytes Merged  IOs Size  RWSize  QLen  Wait SvcTim Util
sda              0      0    0    0  189575      0  554  342     342     2     4      1   95
sdb              0      0    0    0       0      0    0    0       0     0     0      0    0
sdd              0      0    0    0       0      0    0    0       0     0     0      0    0
sde              0      0    0    0       0      0    0    0       0     0     0      0    0
sdc              0      0    0    0       0      0    0    0       0     0     0      0    0
sdf              0      0    0    0       0      0    0    0       0     0     0      0    0

References