Performance degrade when disk related activity

[sankarav]

Hi All,

Production server recently migrated, running HP-UX 11iv1 OS on rp4440,  we have some performance degradation while the disk / tape level backup of filesystems (lvm on EMC clariion storage) being done.    

for the disk level backup we use cp and cpio command to copy the file contents from one filesystem to another filesystem. When this cpio or cp runs, the Glance utility shows Disk Utilization 100%, %wio is 25 - 30% and above , 30 GB of data  back up took more than an hour (1 hr 10 mins). We have dbc_max_pct set to 20.

read & write system call count also high more than 10000 for the cpio process when it is running.

is this  a real performance issue?, customer has reported that disk backup normally completes in less than 30 mins before the migration, After the migration we had introdued the EMC Clarrion SAN luns attached to the server.

Similarly we see high disk utilization when netbackup backup is running on SAN filesystems.

no Powerpath, we are using PVlinks

Could someone suggest is there any tunables that we need to check and set?