I just did a test, and it looks like the duplication
process uses NUMBER_DATA_BUFFERS for both read and write drives. I'm
guessing that there's just a single set of buffers used by both read and write
processes, rather than a separate set of buffers for each
process...
Config on the test system:
# cat
/usr/openv/netbackup/db/config/NUMBER_DATA_BUFFERS 256
# cat
/usr/openv/netbackup/db/config/NUMBER_DATA_BUFFERS_RESTORE 128
Here's the bptm io_init info from the duplication - PID
22020 is the write process, PID 22027 is the read
process:
10:43:20.523 [22020] <2> io_init: using 262144 data
buffer size 10:43:20.523 [22020] <2> io_init: CINDEX 0, sched Kbytes
for monitoring = 20000 10:43:20.524 [22020] <2> io_init: using
256 data buffers 10:43:20.524 [22020] <2> io_init: child delay
= 20, parent delay = 30 (milliseconds) 10:43:20.524 [22020] <2>
io_init: shm_size = 67115012, buffer address = 0xf39b8000, buf control =
0xf79b8000, ready ptr = 0xf79b9800 10:43:21.188 [22027] <2>
io_init: using 256 data buffers 10:43:21.188 [22027] <2>
io_init: buffer size for read is 262144 10:43:21.188 [22027] <2>
io_init: child delay = 20, parent delay = 30 (milliseconds) 10:43:21.188
[22027] <2> io_init: shm_size = 67115060, buffer address = 0xf39b8000, buf
control = 0xf79b8000, ready ptr = 0xf79b9800, res_cntl =
0xf79b9804
Also, there are no lines in the bptm logfile showing
"mpx_setup_restore_shm" for these PIDs...
-devon
Thanks. I guess my
question could be more specifically stated as "does the duplication process
utilize NUMBER_DATA_BUFFERS_RESTORE or NUMBER_DATA_BUFFERS." I don't
have a system in front of me to test.
From: Justin Piszcz
[mailto:jpiszcz AT lucidpixels DOT com] Sent: Wed 11/21/2007 8:58
AM To: Mike Andres Cc: Peters, Devon C;
VERITAS-BU AT mailman.eng.auburn DOT edu Subject: Re: [Veritas-bu] T2000
vaulting performance with VTL/LTO3
Buffers in memory to disk would be dependent on how much cache
the raid controller has yeah?
Justin.
On Wed, 21 Nov 2007, Mike
Andres wrote:
> I'm curious about NUMBER_DATA_BUFFERS_RESTORE and
duplication performance as well. Anybody know this
definitively? > > ________________________________ > >
From: veritas-bu-bounces AT mailman.eng.auburn DOT edu on behalf of Peters, Devon
C > Sent: Tue 11/20/2007 1:32 PM > To:
VERITAS-BU AT mailman.eng.auburn DOT edu > Subject: Re: [Veritas-bu] T2000
vaulting performance with VTL/LTO3 > > > >
Chris, > > To me it looks like there's a 1Gb bottleneck somewhere
(90MB/s is about all we ever got out of 1Gb fibre back in the day). Are
there any ISL's between your tape drive, your switch, and your server's
HBA? Also, have you verified that your tape drives have negotiated onto
the fabric as 2Gb and not 1Gb? > > When we had 2Gb LTO-3 drives on
our T2000's, throughput to a single drive toped out around 160MB/s. When
we upgraded the drives to 4Gb LTO-3, throughput to a single drive went up to
260MB/s. Our data is very compressible, and these numbers are what I
assume to be the limitation of the IBM tape drives. > > Regarding
buffer settings, my experience may not apply directly since we're doing disk
(filesystems on fast storge) to tape backups, rather than VTL to tape.
With our setup we see the best performance with a buffer size of 1048576 and 512
buffers. For us these buffer sizes are mostly related to the filesystem
performance, since we get better disk throughput with 1MB I/O's than with
smaller ones... > > I'm also curious if anyone knows whether the
NUMBER_DATA_BUFFERS_RESTORE parameter is used when doing duplications? I
would assume it is, but I don't know for sure. If it is, then the bptm
process reading from the VTL would be using the default 16 (?) buffers, and you
might see better performance by using a larger number. > > >
-devon > > > ------------------------------------- >
Date: Fri, 16 Nov 2007 10:00:18 -0800 > From: Chris_Millet
<netbackup-forum AT backupcentral DOT com> > Subject: [Veritas-bu]
T2000 vaulting performance with VTL/LTO3 > To:
VERITAS-BU AT mailman.eng.auburn DOT edu > Message-ID:
<1195236018.m2f.181149 AT www.backupcentral DOT com> > > > I'm
starting to experiment with the use of T2000 for media servers. The backup
server is a T2000 8 core, 18GB system. There is a Qlogic QLE2462 PCI-E
dual port 4Gb adapter in the system that plugs into a Qlogic 5602 switch.
>>From there, one port is zoned to a EMC CDL 4400 (VTL) and a few HP LTO3 tape
drives. The connectivity is 4Gb from host to switch, and from switch to
the VTL. The tape drive is 2Gb. > > So when using Netbackup
Vault to copy a backup done to the VTL to a real tape drive, the backup
performance tops out at about 90MB/sec. If I spin up two jobs to two tape
drives, they both go about 45MB/sec. It seems I've hit a 90MB/sec
bottleneck somehow. I have v240s performing better! > > Write
performance to the VTL from incoming client backups over the WAN exceeds the
vault performance. > > My next step is to zone the tape drives on
one of the HBA ports, and the VTL zoned on the other port. > > I'm
using: > SIZE_DATA_BUFFERS = 262144 > NUMBER_DATA_BUFFERS =
64 > > Any other
suggestions? > >
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