[gpfsug-discuss] how gpfs work when disk fail

[atmane khiredine]

dear all

how gpfs work when disk fail

this is a example scenario when disk fail

1 Server

2 Disk directly attached to the local node 100GB

mmlscluster

GPFS cluster information
========================
  GPFS cluster name:         test.gpfs
  GPFS cluster id:           174397273000001824
  GPFS UID domain:           test.gpfs
  Remote shell command:      /usr/bin/ssh
  Remote file copy command:  /usr/bin/scp
  Repository type:           server-based

GPFS cluster configuration servers:
-----------------------------------
  Primary server:    gpfs
  Secondary server:  (none)

 Node  Daemon node name  IP address   Admin node name  Designation
-------------------------------------------------------------------
   1   gpfs         192.168.1.10    gpfs            quorum-manager

cat disk

%nsd:
  device=/dev/sdb
  nsd=nsda
  servers=gpfs
  usage=dataAndMetadata
  pool=system

%nsd:
  device=/dev/sdc
  nsd=nsdb
  servers=gpfs
  usage=dataAndMetadata
  pool=system

mmcrnsd -F disk.txt

mmlsnsd -X

 Disk name    NSD volume ID      Device     Devtype  Node name    Remarks
---------------------------------------------------------------------------
 nsdsdbgpfsa  C0A8000F59DB69E2   /dev/sdb   generic  gpfsa-ib   server node
 nsdsdcgpfsa  C0A8000F59DB69E3   /dev/sdc   generic  gpfsa-ib   server node


mmcrfs gpfs -F disk.txt -B 1M -L 32M -T /gpfs -A no -m 2 -M 3 -r 2 -R 3

mmmount gpfs

df -h

gpfs   200G    3,8G  197G   2% /gpfs  <-- The Disk Have 200GB

my question is the following ??

if I write 180 GB of data in /gpfs
and the disk /dev/sdb is fail
how the disk and/or GPFS continues to support all my data

Thanks

Atmane Khiredine
HPC System Administrator | Office National de la Météorologie
Tél : +213 21 50 73 93 # 303 | Fax : +213 21 50 79 40 | E-mail : a.khiredine at meteo.dz