fbackup speed over network (to LTO)

[Bob Brown_1]

I'm backing up using fbackup over the lan. Both systems (with and w/o the LTO drive) are Gb ethernet.

I know that there are a lot of ideas out there for fbackup config files and I'm trying different combos. What speed in GB/hour should I be expecting as a general rule?

I'm seeing something like 12GB/hour which seems very slow.

I'm thinking of moving blocksperrecord from 256 --> 8192 and keeping records set to 64. Does that sound like a good idea?

thanks!

-Bob

[TwoProc]

Bob, usually the problem with slow throughput is the inability to keep data streaming to the tape drive at an appreciable rate so that it doesn't have to stop/start and resync constantly. I don't know if you've got an LTO or an LTO-2 drive, but an (HP) LTO-2 drive system has technology in it to slow down the tape to more evenly match the data rate to try and attempt a streaming write to the tape device. Sadly, no "freebie" tools on your HP will give you much throughput compared to more expensive enterprise-class software that is built to overcome this issue. I saw the big jumps in performance when I gave up on fbackup, cpio, tar, etc years back and began using Omniback (now Data Protector). So, while I think you should go ahead and try to changing the parameters as per your note, I don't think you're going to signifigant improvement like you're hoping for until you've got something better to back up with. I highly recommend HP's DataProtector 5.5 to get fast backup and recovery times that you would like.

[Bob Brown_1]

I know...I just need to know what's the best way to get the best throughput with fbackup over a lan to lto until we settle on a network-wide backup scheme.

What's the best way to get the best from fbackup in my situation for the present?

thanks.

-Bob

[rick jones]

What are the systems, and which GbE cards are involved? In general, the more you can make the transfer look like FTP the better. That is to say bulk transfer. Also, making sure the window sizes used are suitably large - the HP-UX default of 32KB may not be sufficient.

This of course, completely ignores any tape issues.

[Bob Brown_1]

Well...I experimented and got MUCH better results. I'm up to >40GB/hour right now.

I set blocksperrecord to 8192,
records to 64,
checkpointfreq to 4096

Those made the biggest difference.

-Bob