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mad_jock's avatar
mad_jock
Level 3
10 years ago

backup to disk write issues

Hello I'm new to netbackup after 5 years with HP Data Protector and I have some real concerns about write to disk performance. It appears that we have queues waiting for the block to empty so we c...
7.5
Backup and Recovery
NetBackup
  • watsons's avatar
    watsons
    10 years ago

    write_data: waited for full buffer 388 times, delayed 1457 times

    From my experience, the above, if it is a backup job, does not look too bad. But the bottleneck should be on client read I/O or network between media server and client. 

    If writing to disk is slower than it reads from client, you should see a higher delay of "waited for empty buffer", not the "full buffer". 

    Anyway,, you said the media server is Netbackup Appliance 5220, but what version (2.5.x or 2.6.x)?  It is better you start generating a DataCollect for Netbackup Support team to review, have them pointed out if there is any hardware problems that could degrade the performance. 

    Netbackup Appliance does come with a tool to check disk I/O using nbperfchk:

    http://www.symantec.com/docs/HOWTO101014

    The above technote is for your reference, do not simply change the setting unless you have confirmation from Support team.

mad_jock's avatar
mad_jock
Level 3
10 years ago

Hi Marianne

 

here are some more details please note the complete log is massive.

 

00:29:43.392 [14462] <2> write_data: twin_index: 0 active: 1 dont_process: 0 wrote_backup_hdr: 0 finished_buff: 0 saved_cindex: -1 twin_is_disk 1 delay_brm: 0
00:29:43.392 [14462] <2> write_data: Total Kbytes transferred 0
00:29:43.392 [14462] <2> write_data: first write, twin_index: 0 cindex: 0 dont_process: 1 wrote_backup_hdr: 0 finished_buff: 0
00:29:43.392 [14462] <2> write_data: received first buffer (1048576 bytes), begin writing data
00:29:43.464 [14462] <2> send_media_kbytes_written_establish_threshold: CINDEX 0, RB Kbytes for monitoring = 3000000
00:30:10.666 [14462] <2> write_data: writing block shorter than BUFF_SIZE, 262144 bytes
00:30:10.668 [14462] <2> write_data: writing short block, 262144 bytes, remainder 0
00:30:10.668 [14462] <2> write_data: waited for full buffer 388 times, delayed 1457 times
00:30:10.668 [14462] <2> write_data: Total Kbytes transferred 499968
00:30:10.668 [14462] <2> write_backup: write_data() returned, exit_status = 0, CINDEX = 0, TWIN_INDEX = 0, backup_status = 0
 

We have been experiencing alot of performance issues and i think the disk on the 5220 cant cope with what we are backing up.

I need to find out if extra media servers would help with the backlog of over running jobs would help.