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Re: Slow Backup with Ultrium 460

 
Ronald W. Satz
Advisor

Re: Slow Backup with Ultrium 460

Dave:

I ran the PAT12 tests several times. For the image backup test the results are 50.64 and 50.81 MB/sec. For the quick test the results are 5.12, 9.19, and 8.58 MB/sec. For the real test, the results are .84, 3.25, and 2.23 MB/sec, depending on which directories I chose.

So, does Tapeware do image backups?

Regards,
RWS
tranapower@aol.com
Ronald W. Satz
Advisor

Re: Slow Backup with Ultrium 460

I received the Tapeware CD today and installed the program. I did not see any image backup option so I proceeded to do a file backup to tape. The result: 92 MB/min--very poor.

NovaBack won't have a version of InstantRecovery (which does an image backup) which can work with the 39320 until June. So does anyone out there have a recommendation for a good tape image backup program?

Regards,
RWS
transpower@aol.com
Ronald W. Satz
Advisor

Re: Slow Backup with Ultrium 460

I attempted to upload the LTT support ticket--but it was a bit more than the 1 MB limit. So I sent it to what I thought was Dave Dewar's e-mail address.

Regards,
RWS
transpower@aol.com
Dave Dewar
Trusted Contributor

Re: Slow Backup with Ultrium 460

Hi,

Ok, it does look like image backup is your only option to get fast backup rate unless you want to invest in a DISK ARRAY RAID system. Your issue is basically that you have a extremely fast tape drive that is being supplied by a less than stellar disk subsystem. You LaCie disks (actually maxtorAltas320) are fast in sequential/image mode, but as soon as you put a filesystem on them you come up against the standard filesystem speed issues many users face. A disk array raid system would allow you to overcome these issues. However, this would cost several K dollars. Something like HP's MSA30 with 4-6 hard disks would be an option. You could partition this array to support both you linux and windows operating system fairly easily. You would also have to buy a SCSI RAID controller for your server. However, this would obviously mean further investment on your part, hence, the image backup option alternative below.

You have two options for image backup.

1. You could operate a 2 stage process where you use something like norton ghost or diskimage to create an image of your target filesystem on either a 3rd disk (preferable) or the same disk if you have space. You can then backup this image using something like tapeware and should acheive very close to image backup performance since you will be backing up a single large continous file.

2. Use a backup application that supports image backup. Premier ISV appls like Arcserve and Netbackup/BackupExec support image backup but the licenses are not cheap. You can go to the respective companies websites to download trial versions I think before buying. These do support Ultrium 460.
There are a couple of other ISV appl that are specifically geared to image backup. Ultrabac and Snapback are two I know of. I do not know of the support status of these for Ultrium 460, however, again you can download trial versions of these appls for free and try them out.

Please remember that with image backup, you are backing up an image of the disk, consequently it is very difficult and in many cases impossible to do single file restores. Image backup is targetted at disaster recovery rather than single file restore. The links I posted previously explain this more fully.

If you want single file restore you will have to use the standard backup mode with its associated performance bottlenecks due to your disk subsystem.

I did receive the support ticket, thanks. Your scsi config is fine, you are operating in 320 SCSI mode and your drive is healthy. You will come across another performance issue if you want to backup your disk that resides on the same scsi channel as your tape drive. It is much better to have the tape drive on a separate scsi channel to the target hard disks.

Cheers,

Dave Dewar
Ronald W. Satz
Advisor

Re: Slow Backup with Ultrium 460

I obtained the Snapback program and was able to create a 73 GB tape image in 33 minutes--better than 2 GB/min. However, to date, creating the DOS recovery diskette has failed. Snapback creates a bootable diskette using "Free DOS"--but it doesn't seem to be compatible with the Ultra320 ASPI. So I tried PC-DOS 7 and at least got the ASPI to load; however, there are problems with emm386.exe (remember that?) and even if I get into the Snapback recovery program it doesn't recognize the tape drive. So I guess I'll wait for the new version of InstantRecovery.
Dave Dewar
Trusted Contributor

Re: Slow Backup with Ultrium 460

Hi Ron,

Good to hear that you got a image backup working and demomstrated a good throuhput to your tape drive. Your speed appears to be about 36MB/s so my guess is you have some hardware compression going on since you are acheiving greatr than the 30MB/sec native speed often Ultrium 460. We have proved that your drive will go fast enough if you have the appropriate disk subsystem/backup appl combination to keep it satisfied. I am just sorry that Snapback hasn't worked for you.
Hopefully, InstantRecovery will meet you needs when it comes out in June. Let me know how you get on.

Cheers,

Dave Dewar
Ronald W. Satz
Advisor

Re: Slow Backup with Ultrium 460

It's been months since I last posted. But now the problem is essentially solved: by setting XP to "adjust for best performance of system cache" (not programs) and setting System Mechanic to commit the cache every 2 seconds. With this, backing up 13,359,201,608 bytes took just 20 minutes! This is approx. 668 MB/min, certainly acceptable.
Dave Dewar
Trusted Contributor

Re: Slow Backup with Ultrium 460

Ron,

Thanks for the update. Good to hear for you and pleased that you have found a solution that gives you acceptable performance.

Cheers,

Dave Dewar