NEEDSYNC flag on raid 5 volume

[Anbu]

When I run the
For Raid5 volume it marks volume display as NEEDSYNC

when stop and start the volume , it does resync operation.
What exactly this doing is not clear to me, doest it writes entire data or just creating the
raid logs ? Any idea ?

vxassist -g srcdg make raid 500M layout=raid5 init=active

v raid raid5 ENABLED 1024032 - NEEDSYNC - -
pl raid-01 raid ENABLED 1024032 - ACTIVE - -
sd sdaq-02 raid-01 ENABLED 341344 0 - - -
sd sdh-02 raid-01 ENABLED 341344 0 - - -
sd sdg-01 raid-01 ENABLED 341344 0 - - -
sd sdj-02 raid-01 ENABLED 341344 0 - - -
pl raid-02 raid ENABLED 3840 - LOG - -
sd sdi-02 raid-02 ENABLED 3840 0 - - -

[Gaurav_S · Accepted solution]

Hello Anbu,

When you are specifying init=active in the vxassist command, you are stopping the initial resync of RAID5 volume. Basically when a RAID 5 volume is created, in a layman language has to attach/map the RAID5 log with its stripes which is must for RAID 5 log to track all the writes happening on the stripes.

Irrespective of whether you use init=active or not, RAID 5 log will be surely created, unless you specify a nolog option.

In case you remove the init=active option from above command, the command will take some time to return but will complete initial sync & will come back... you should then see volume Enabled Active...

Hope this helps..

Gaurav

[prax]

Hi Anbu,

Gaurav has clearly pointed out about usage of init=active.

Instead of writing the command like wise you can also rewrite it as:
# vxassist -g srcdg make myraid 500M layout=raid5
# vxvol init active myraid or # vxvol init zero myraid  ->> u wud see the volume as ACTIVE


Cheers,
prax