Monday, December 30, 2013

Linux login issue - Can not login: Resource temporarily not available

Sometime we get following error while user login:

$su - username
Coud not login: Resource temporarily not available

Most of the times this is because of processes or number of files available to user is already used. So, could not arrange more files/processes to login, in this case we required to increase the limits for user in /etc/security/limits.conf (PAM module)

username        soft    nproc           3000
username        hard    nproc          4096
username        soft     nofile           6000
username        hard    nofile          8192

Set these values as per requirement else setting up these values higher may result in server inaccessible in case that particular uses all file descriptors, process and higher memory of server.

Monday, December 2, 2013

Linux Resize LUN Without Reboot

Try running following commands

Check OS using what devices for attached LUNs:

multipath -l

mpath5 (360060.......................) dm-15
[size=100G][features=1 queue_if_no_path][hwhandler=1 emc][rw]
\_ round-robin 0 [prio=0][active]
 \_ 1:0:0:14 sdb 66:192 [active][undef]
 \_ 0:0:0:14 sdc  8:224  [active][undef]
\_ round-robin 0 [prio=0][enabled]
 \_ 0:0:1:14 sdd 66:112 [active][undef]
 \_ 1:0:1:14 sde 67:176 [active][undef]

Rescan all paths:
echo 1 > /sys/block/sdb/device/rescan
echo 1 > /sys/block/sdc/device/rescan
echo 1 > /sys/block/sdd/device/rescan
echo 1 > /sys/block/sde/device/rescan

Then run:
multipathd -k

resize map mpath5
If LVM is used, also required following:
Check Disk Changes detected under LVM:
  Check VG Size is Increased:
Now Extend the LV: 
#lvextend -L +G
Finally Extend the File System
Thats it!!!