VectorLinux
September 30, 2014, 05:41:28 am *
Welcome, Guest. Please login or register.
Did you miss your activation email?

Login with username, password and session length
News: Visit our home page for VL info. To search the old message board go to http://vectorlinux.com/forum1. The first VL forum is temporarily offline until we can find a host for it. Thanks for your patience.
 
Now powered by KnowledgeDex.
   Home   Help Search Login Register  
Please support VectorLinux!
Pages: [1]
  Print  
Author Topic: tmpfs and shm confusion  (Read 2557 times)
roarde
Vectorian
****
Posts: 530


move the needle


« on: February 12, 2011, 03:30:37 am »

Should tmpfs and shm both be mounted at /dev/shm?

Code:
roarde:$ df
Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/sda2             43944444  13103672  30840772  30% /
tmpfs                   222084         0    222084   0% /dev/shm
shm                     222084         0    222084   0% /dev/shm

roarde:$ mount -l
/dev/sda2 on / type reiserfs (rw,noatime)
tmpfs on /dev/shm type tmpfs (rw)
usbfs on /proc/bus/usb type usbfs (rw,devmode=0666)
shm on /dev/shm type tmpfs (rw)

roarde:$ grep "^tmpfs\|^shm" /etc/fstab
tmpfs   /dev/shm    tmpfs defaults 0  0
shm            /dev/shm     tmpfs  defaults        0     0

Trying to track down a performance issue. There's a disk access problem and also processor cache (!) seems to be turned off.
Logged

Robert
VL STD 7.1 RC2.2.2, icewmvmods
nightflier
Administrator
Vectorian
*****
Posts: 4024



« Reply #1 on: February 12, 2011, 05:17:29 am »

Not sure about your configuration, shm and tmpfs is not the same.

I found a good fstab guide here: https://wiki.archlinux.org/index.php/Fstab
scroll down to the tmpfs section.
Logged
rm-r
DoucheBag
Vectorite
***
Posts: 115


« Reply #2 on: February 15, 2011, 09:30:02 am »


HI ~ Don't know if this may help:

Generally - if fstab is mis-configured, an error complaint by kernel is output to screen @ bootup

Have you read the /var/log/dmesg file ~ This /var/log directory also contains other helpful log files
In some cases, /tmp content may hold clues (unless a cron task has been set to MT  temporary files)   

Fstab Example:

   proc      /proc      proc   defaults      0 0  <== mandatory_
   shm      /dev/shm   tmpfs   nodev,nosuid,noexec   0 0 <== usual default
 > none       /mnt/tmpfs    tmpfs  <== see URL

http://www.ibm.com/developerworks/library/l-fs3.html

Caveat - Tmpfs is "booted" session only - until set as above
Shared memory file system is a "virtual" file management concept
tmpfs  is similar to an initrd content -( temporary)  - usage may be  as suggested in URL
 
What is the access Problem - drive not found/mounted, DMA *probe not read,  in/out reads fail:

*Hdparm will give drive data -@  present settings
 
Processor cache would be  a hardware BIOS setting, unless cpu Cfg  utility has  been installed, mis-applied 
'Tho'  I am unaware of any such capability in either

(Without a level one or two CPU cache, you should experience MANY weird results)

Logged

"Problems are seldom resolved by thinking in the same manner they were created"

"What is viewed is not important - That which is seen is"
Pages: [1]
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.19 | SMF © 2013, Simple Machines Valid XHTML 1.0! Valid CSS!