Thank you for your reply. Below are extra info. GFS2 partition in question: [root@apps03 ~]# df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/SAN5020-order 800G 435G 366G 55% /sanstorage/data0/images/order <- one that suffered from slow down /dev/mapper/SAN5020-SNPimage 3.0T 484G 2.6T 16% /sanstorage/data0/ShotNPrint/SNP_image /dev/mapper/SAN5020-data0 1.3T 828G 475G 64% /sanstorage/data0/images/album normal nodes, copying a 200MB file to affected GFS2 partition [root@apps01 ~]# time cp 200m.test /sanstorage/data0/images/order/ real 0m1.073s user 0m0.008s sys 0m0.996s [root@apps08 ~]# time cp 200m.test /sanstorage/data0/images/order/ real 0m5.046s user 0m0.004s sys 0m1.398s affected node, 1/30th the normal throughput atm. I cannot reproduced the extreme slow down due as the problem reccurs in strochastic manner. but this is not rare since this week. [root@apps03 ~]# time cp 200m.test /sanstorage/data0/images/order real 0m30.885s user 0m0.006s sys 0m6.348s affected node, writing to different export from the same SAN storage(an IBM DS5020) [root@apps03 ~]# time cp 200m.test /sanstorage/data0/ShotNPrint/SNP_image real 0m2.353s user 0m0.006s sys 0m2.033s [root@apps03 ~]# time cp 200m.test /sanstorage/data0/images/album real 0m2.319s user 0m0.010s sys 0m1.798s As the connection topology is single fibre pair connected to central SAN switch in a star topology, without any redundant path, if there are hardware issue SAN5020-SNPimage/SAN5020-data0 should be affected too, but that is not the case -- Linux-cluster mailing list Linux-cluster@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-cluster
