multipath iscsi nfs - backup issues

[svacaroaia]

Hi,
Backups are very slow and , eventually crash the servers

an excerpt from syslog shows:
" ... kernel: ct0 nfs: server 10.10.19.49 not responding, still trying "
" .. pvestatd[30186]: WARNING: command 'df -P -B 1 /mnt/pve/hugebackup' failed: got timeout .."

I am pretty sure my configuration is faulty and would appreciate hints or constructive criticism

Here is how I am doing it
I am providing a 10TB target from NAS to one of my servers
configure multipath and create an ext4 filesytem on it using partd
create a phisical volume
mount it with _netdev option
create an nfs backup storage

Here are the relevant settings

On the NFS server:
root@blh02-14:~# iscsiadm -m session

tcp: [15] 10.10.30.22:3260,1 iqn.2012-12.nas01-01.pcasinc.comroxmoxbackup
tcp: [16] 10.10.30.21:3260,1 iqn.2012-12.nas01-01.pcasinc.comroxmoxbackup

multipath -ll
mpath2 (360014052e1189200058d004000000000) dm-97 LIO-ORG,FILEIO
size=9.8T features='1 queue_if_no_path' hwhandler='0' wp=rw
`-+- policy='round-robin 0' prio=2 status=active
|- 17:0:0:0 sdx 65:112 active ready running
`- 16:0:0:0 sdw 65:96 active ready running


parted /dev/proxbackup/proxbackup
GNU Parted 2.3
Using /dev/dm-105
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) print
Model: Linux device-mapper (linear) (dm)
Disk /dev/dm-105: 10.7TB
Sector size (logical/physical): 512B/512B
Partition Table: loop


Number Start End Size File system Flags
1 0.00B 10.7TB 10.7TB ext4





pvdisplay
--- Physical volume ---
PV Name /dev/disk/by-id/dm-name-mpath2
VG Name proxbackup
PV Size 9.77 TiB / not usable 3.00 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 2559999
Free PE 0
Allocated PE 2559999
PV UUID vllhez-pMf0-Xtnp-M1XX-b5TH-Fzsb-w1hwBb

cat /etc/fstab
/dev/proxbackup/proxbackup /backups ext4 auto,defaults,_netdev 0 0


cat /etc/exports
/backups 10.10.19.0/255.255.255.0(rw,sync,no_subtree_check,no_root_squash)


cat /etc/pve/storage.cfg
nfs: hugebackup
path /mnt/pve/hugebackup
server 10.10.19.49
export /backups
options timeo=20,retrans=5,rsize=8192,wsize=8192,intr,vers=4,proto=tcp
content iso,backup
maxfiles 5

pveversion -v
pve-manager: 2.2-31 (pve-manager/2.2/e94e95e9)
running kernel: 2.6.32-16-pve
proxmox-ve-2.6.32: 2.2-82
pve-kernel-2.6.32-11-pve: 2.6.32-66
pve-kernel-2.6.32-16-pve: 2.6.32-82
pve-kernel-2.6.32-14-pve: 2.6.32-74
lvm2: 2.02.95-1pve2
clvm: 2.02.95-1pve2
corosync-pve: 1.4.4-1
openais-pve: 1.1.4-2
libqb: 0.10.1-2
redhat-cluster-pve: 3.1.93-2
resource-agents-pve: 3.9.2-3
fence-agents-pve: 3.1.9-1
pve-cluster: 1.0-33
qemu-server: 2.0-69
pve-firmware: 1.0-21
libpve-common-perl: 1.0-39
libpve-access-control: 1.0-25
libpve-storage-perl: 2.0-36
vncterm: 1.0-3
vzctl: 4.0-1pve2
vzprocps: 2.0.11-2
vzquota: 3.1-1
pve-qemu-kvm: 1.2-7
ksm-control-daemon: 1.1-1