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how to troubleshoot slow vm backup

Level 3

I m using netbackup 9.1 to backup vm.

All is running fine except the backup of a particuliar vm that is extremely slow. 

the vmdk is 800Go size ans it take more than 12 hours to backup

i have CBT enabled , i have the accelerator enabled. 

is there some way to improve the speed. 
Here is the output of backup

BEGIN_WRITING 1678239682
LOG 1678276628 4 bpbkar 13924 INF - Transport Type = hotadd
LOG 1678277288 4 bpbkar 13924 accelerator sent 32837355520 bytes out of 824100023296 bytes to server, optimization 96,0%
LOG 1678277288 4 bptm 13452 waited for full buffer 5710 times, delayed 2457281 times
LOG 1678277315 4 bptm 13452 EXITING with status 0 <----------
LOG 1678277315 4 13452; Report=PDDO Stats for ( scanned: 805599404 KB,
CR sent: 7516980 KB, CR sent over FC: 0 KB, dedup: 99,1%, cache disabled, where dedup space saving:97,4%, compression space saving:1,6%
LOG 1678277315 4 bpbrm 13337 validating image for client
LOG 1678277315 4 bpbkar 13924 done. status: 0: the requested operation was successfully completed
END_WRITING 1678277455
Started 1678239673
KbPerSec 21423
Kilobytes 804785188
Files 5163970
ActivePid 13337
Status 0
DestStorageUnit dedup-stu
Transport 0
Ended 1678277456


Level 6
Partner    VIP    Accredited Certified

You omit the time in front of each line, and this makes it difficult for us to understand the problem.

So, to make it easier to read, I manually added the time.

Wednesday, March 8, 2023 1:41:22 AM BEGIN_WRITING
Wednesday, March 8, 2023 11:57:08 AM bpbkar 13924 INF - Transport Type = hotadd
Wednesday, March 8, 2023 12:08:08 PM bptm 13452 waited for full buffer 5710 times, delayed 2457281 times

So what I understand is that the real backup (the reading of the blocks) starts at 11:57:08 AM and the backup ends at 12:08:08 PM. Witch is fast. Only 32 GB of data was backed up (96% acceleration)
The problem is to understanding what netbackup is doing from 1:41:22 AM until 11:57:08 AM.
There is a possibility that other backups run at the same time and a restore limit is reached

Can you run a manual backup at a time that any other backup run?
open the bpbrm log on the media server and bpbkar log on the backup host

Hi Stefanos

Thanks for the reply

Indeed i have missed this peculiar point. 

but when i look at my log i read

Wed Mar 8 02:41:22 CET 2023 BEGIN_WRITING 1678239682

the process seem begin to write a 02:41:22

I have read the logs in my backup host for bpbkar process

2:39:01.494 [13924.13924] <2> bpbkar main: previous backup id list:<ares.genoscope.cns.fr_1678152019,ares.genoscope.cns.fr_1678152019>
02:39:01.496 [13924.13924] <2> logparams: bpbkarv -r 2678400 -dt 0 -to 0 -bpstart_time 1678239973 -clnt -class BCKP_VM -sched Bckp_VM_quotidien -st FUL
L -bpstart_to 300 -bpend_to 300 -read_to 900 -ru root -stream_count 244 -stream_number 244 -jobgrpid 1401182 -blks_per_buffer 512 -use_otm -fso -ifr -pid 13337 -mediasvr net -bt 1678239673 -t 0 -b ares.genoscope.cns.fr_1678239673 -kl 7 -fi -S -fim NONE -ct 40 -fscp -S -storagesv
r -bidlist bid@BCKP_VM_ares.genoscope.cns.fr_1678239673
02:39:01.498 [13924.13924] <4> bpbkar main: INF - setenv BACKUPID=ares.genoscope.cns.fr_1678239673
02:39:01.610 [13924.13924] <4> bpbkar expand_wildcards: start to backup filelist /usr/openv/netbackup/online_util/fi_cntl/bpfis.fim.ares.genoscope.cns.fr_1678239638.1.0.NBU_
DATA.xml ,nb_fscp_enabled is 1
02:39:01.610 [13924.13924] <4> bpbkar expand_wildcards: INF - Processing /usr/openv/netbackup/online_util/fi_cntl/bpfis.fim.ares.genoscope.cns.fr_1678239638.1.0.NBU_DATA.xml
02:39:01.623 [13924.13924] <4> bpfsmap: INF - bpfsmap: arg list: brmpid 13337 rawdisk /usr/openv/netbackup/online_util/fi_cntl/bpfis.fim.ares.genoscope.cns.fr_1678239638.1.0
.NBU_DATA.xml datafd -1 inctime 0
02:39:01.623 [13924.13924] <4> bpfsmap: INF - bpfsmap butime 1678239673 clientname hostname buid ares.genoscope.
02:39:01.634 [13924.13924] <4> logBackupInfo: INF - Backing up vCenter server, ESX host, BIOS UUID 422a7ebc-9a88-2b6e-b400-651816baeab
f, Instance UUID 502ac048-319b-00eb-2efe-7188e85bd472, Display Name, Hostname
13:08:08.025 [13924.13924] <4> bpbkar expand_wildcards: end backup for filelist /usr/openv/netbackup/online_util/fi_cntl/bpfis.fim.ares.genoscope.cns.fr_1678239638.1.0.NBU_D

the bpbkar start at 2h39 and finish at 13h08.

I m wondering if i should consider it slow or not 




Level 2

Due to insufficient information so we are unable to understand your problem. 

Level 4

it looks like you are using hotadd transport mode, did you tried nbd  to test

Level 2

Have you resolved your problem? If yes, then let me know how you resolved your problem so that I have more information about problem-solving as I am struggling with the balloon business and trying hard to solve the issues.


No i didn"t try try as this vm is one of 200+ VM we backup. 

On my netbackup training it was told that hotadd is better than nbd. 

I will make that test uin my next backup 

No i haven't yet but new problem arise then i haven't time to cope with this peculiar one. 

I will post here if i find a solution