OESF Portables Forum

General Forums => General Discussion => Topic started by: ShiroiKuma on July 03, 2006, 06:48:31 am

Title: Bzip Or Only Tar Via Usb
Post by: ShiroiKuma on July 03, 2006, 06:48:31 am

I have a 3200 and want to back up the harddrive, which is full, cca 6 gig...

So what I'm gonna do, is attach an iPod or external harddrive via the USB, and back up the data there.

Now considering USB write to an external harddisk is slow, but tar bzipping the files is also slow due to the Z's processor, what would be better in this case.

Explanation, I can't pre tar, or pre tar bzip the files to a CF or the harddrive itself because it's full, so I'm gonna launch either tar or tar bzip directly from the Z to write to the external harddisk.

Option 1: tar the files to the external harddisk, which will mean more data to be sent over the USB, but no slowing down due to compressing the data by the Z's processor.

Option 2: tar bzip the files to the external harddisk, which will mean less data to be sent over the USB, but being slower due to bzipping the files by the Z's processor.

Which option will result in a faster execution of the whole process.

It will surely take a number of hours, but what would be the recommendation?

Title: Bzip Or Only Tar Via Usb
Post by: lardman on July 04, 2006, 07:38:36 am

You may spend more time working out the optimum solution than it takes to actually choose one and get on with it

Anyway it sounds like an interesting optimisation task. You need to work out roughly what level of compression (and therefore time/mb) your data will produce vs the transfer speed.

A couple of test runs to work out bzip compression speed (for the average file) and usb transfer speed will give you enough info to work out the fastest way, or you might want to optimise depending on file type, so you don't bother compressing certain types, which will transfer faster uncompressed than compressed + compression time.


Si

Title: Bzip Or Only Tar Via Usb
Post by: speculatrix on July 04, 2006, 08:48:31 am

maybe you'd be better of using rsync to copy the files, that way you can restart the copying if it fails as rsync will see if the target already exists, and rsync has its own compression modes.

Title: Bzip Or Only Tar Via Usb
Post by: speculatrix on July 04, 2006, 08:49:00 am

p.s. you could use rsync to copy the files to a desktop computer using usb networking instead, or use wifi?

Title: Bzip Or Only Tar Via Usb
Post by: ShiroiKuma on July 04, 2006, 09:00:13 am

Yep, good suggestion. However I need to archive to a FAT volume, so can't use rsync and have to somehow tar and/or compress.  

Title: Bzip Or Only Tar Via Usb
Post by: lardman on July 04, 2006, 10:30:57 am

Could you not mount the drive as a mass storage device and perform the compression on the desktop machine (not the optimum solution in terms of time, but at least you'll get everything compressed quickly)? Or is the HDD (in the Z) not FAT formatted (I thought they were)?


Si

Title: Bzip Or Only Tar Via Usb
Post by: ShiroiKuma on July 04, 2006, 10:43:04 am

Quote

Could you not mount the drive as a mass storage device and perform the compression on the desktop machine (not the optimum solution in terms of time, but at least you'll get everything compressed quickly)? Or is the HDD (in the Z) not FAT formatted (I thought they were)?
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Yep, I reformatted the HD to ext3, so have to do it from the Z.

Title: Bzip Or Only Tar Via Usb
Post by: lardman on July 04, 2006, 12:04:20 pm

An option:

http://www.fs-driver.org/ (http://www.fs-driver.org/)


Si