For our SAN media servers, we do see restore performance gains with this setting. The difference between the default setting, and 512 has been around 20% for us. We haven't done a whole lot of tuning or analisys on this - I just set it to match NUMBER_DATA_BUFFERS. :)
For our less high-performance backups (i.e. anything going over the network) I've never looked into it. -devon -----Original Message----- From: Justin Piszcz [mailto:[EMAIL PROTECTED] Sent: Wednesday, November 21, 2007 4:05 PM To: Peters, Devon C Cc: Mike Andres; VERITAS-BU@mailman.eng.auburn.edu Subject: RE: [Veritas-bu] T2000 vaulting performance with VTL/LTO3 Has anyone here done benchmarks to see what type of potential speed up is gained with the NUMBER_DATA_BUFFERS_RESTORE directive? On Wed, 21 Nov 2007, Peters, Devon C wrote: > 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 > > ________________________________ > > From: Mike Andres [mailto:[EMAIL PROTECTED] > Sent: Wednesday, November 21, 2007 9:49 AM > To: Justin Piszcz > Cc: Peters, Devon C; VERITAS-BU@mailman.eng.auburn.edu > Subject: RE: [Veritas-bu] T2000 vaulting performance with VTL/LTO3 > > > 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:[EMAIL PROTECTED] > Sent: Wed 11/21/2007 8:58 AM > To: Mike Andres > Cc: Peters, Devon C; VERITAS-BU@mailman.eng.auburn.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: [EMAIL PROTECTED] on behalf of Peters, > Devon C >> Sent: Tue 11/20/2007 1:32 PM >> To: VERITAS-BU@mailman.eng.auburn.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 <[EMAIL PROTECTED]> >> Subject: [Veritas-bu] T2000 vaulting performance with VTL/LTO3 >> To: VERITAS-BU@mailman.eng.auburn.edu >> Message-ID: <[EMAIL PROTECTED]> >> >> >> 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? >> >> > > > _______________________________________________ Veritas-bu maillist - Veritas-bu@mailman.eng.auburn.edu http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu