using fbackup and DLT

[Diane Cardone]

It has been suggested to me to use fbackup instead of tar to speed up my backup times. Since I am not that familiar with fbackup I wanted to get some feedback/recommendations from people that are currently using it.
I will probably do full backups each night rather than incremental. I will be backing up 40-50 gig to a DLT8000. Can anyone give me and idea of what an acceptable time to back that amount of data up? Also, how easy would it be if I needed to recover anything from the fbackup tape?

Thanks in advance.
DKM

[Sebastian Galeski_1]

Hi
If You want to do backup fbackup is very nice command and it is default command for backup in pure HPUX:
#fbackup -f /dev/rmt/1m -i / -e /tmp will backup all filesystem from / and exclude /tmp.

Of course You can use tar or cpio or dd with DLT but thats tool are not for backup, they store data on tape.

If You had installed Ignite/UX use make_recovery or make_tape_recovery to create tape which create bootable tape with UNIX.

AS advanced solution for backup you can use Omniback, but unfortunately You have to pay for this software.

look to:
man fbackup
man make_recovery

hope it help You

[steven Burgess_2]

Hi

Have a look at this thread for more information on fbackup - incrementals and commands

http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0x4438eea29889d611abdb0090277a778c,00.html

Regards

Steve

[Alun Territt_1]

Diane

We have an N-Class & K-Class doing fbackup of about 80G.

As a rough figure, we backup 1G about every 3 mins (give or take). It all depends if you are backing up lots of small files or lots of big files.

Also, as a rough indication, recovery takes about 4.5-6 mins per G.

Hope this helps :).

Alun

[Diane Cardone]

Alun,
Thank you for the information, it will be very helpful in my testing. We are also running on a K-class machine. Would you be willing to share with me some of your parameter values you use within your config file for fbackup?

DKM

[steven Burgess_2]

Diane

I see you are a new forum user. You can assign points as a sign of thanks for those that have helped you.

Here are the recommended config values for fbackup

blocksperrecord 256
records 32
checkpointfreq 1024
readerprocesses 6
maxretries 5
retrylimit 5000000
maxvoluses 200
filesperfsm 2000

You enter these in a file and invoke them through the -c option when using fbackup

fbackup -v -f /dev/rmt/0m -c / -i

man fbackup

for explanations on the paramters

HTH

Steve

[Alun Territt_1]

It is probably very niave, but we do not use a config file.

I think Steve's comments will help both you and me. (Nice one Steve).

Alun

[Diane Cardone]

Thank you very much for the information. I am going to begin testing with the fbackup this weekend.

DKM

[Frank Slootweg]

DLT8000 has a Native Mode (= uncompressed) *maximum* speed of 6.0MByte/sec, i.e. (about) the 1GByte per 3 minutes which Alun mentioned.

So if you get that kind of speed or more, then good on you, and no software can increase the *speed*.

If you get *much* less than that speed, then your configuration is not optimal and you will cause heavy wear to both the media and the drive. Not good. See the other responses for possible solutions.

[Bill Hassell]

One additional note: in order for the tape drive to sustain the maximum transfer speed, it *must* be on a dedicated SCSI interface. If the DLT is shared with other devices, specifically disks that are part of the backup set, performance can degrade 20:1 to 100:1 because of repositioning due to data starvation. DLT (and DDS) tape drives use data streaming technology but if the stream is interrupted, repositioining can take seconds.

[Sanjay_6]

Hi Diane,

Maybe these links can help,

http://docs.hp.com/cgi-bin/fsearch/framedisplay?top=/hpux/onlinedocs/B2355-90742/B2355-90742_top.html&con=/hpux/onlinedocs/B2355-90742/00/00/51-con.html&toc=/hpux/onlinedocs/B2355-90742/00/00/51-toc.html&searchterms=fbackup%20tar&queryid=20020711-072326

http://support2.itrc.hp.com/service/cki/search.do?searchString=KBRC00000196&mode=id&submit=Search&searchCrit=allwords&docType=Security&docType=Patch&docType=EngineerNotes&docType=BugReports&docType=Hardware&docType=ReferenceMaterials&docType=ThirdParty

Hope this helps.

Regds

[Diane Cardone]

Does the speed decrease when using compression?

[Frank Slootweg]

> Does the speed decrease when using compression?

No, if all is well, the speed should *in*crease when using compression. I.e. if your data is compressable by a factor of two and everything else is perfect (Yeah right! :-)), you *could* *theoretically* get a maximum speed of 12MByte/second (instead of 6 uncompressed).

[Ray Carlson]

I would like to add just a little more to what Bill Hassell mentioned about having the DLT on a dedicated SCSI channel. Other than taking a performance hit during backups because the DLT is not on a dedicated channel, your backup may look fine. However, when you try to restore, you may not be able to. We found that if the DLT was not on a dedicated SCSI channel, the recovery would often fail with an I/O error. After moving the DLT to a dedicated SCSI channel, we could successfully restore using the same tapes that gave I/O errors when the DLT was on a SCSI channel with some other devices.

[Diane Cardone]

I have verified that the DLT has a dedicated SCSI card.

I want to thank everyone again for their feedback, it's exectly what I have been looking for, people that have real time experience with a problem/situation!

DKM

[Frank Slootweg]

Thanks for the feedback.

You may want to assign points to *all* responses, even if you only assign 0 points or label the points field as "N/A". Do not leave responses "unassigned".

Why? Because only responses with points or N/A count for *your* "This member has assigned points to X of Y responses to his/her questions." score. If your score is low, i.e. X is much less than Y, then people are less likely to help you, because it *looks* like you are not willing to thank the respondents for their efforts.

[Please 0 points or "N/A" for *this* response.]