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-   -   Testing SD!... Slow over network? (http://www.shirt-pocket.com/forums/showthread.php?t=870)

simon 12-02-2005 06:29 AM

Testing SD!... Slow over network?
 
I am testing out SD! and I am trying to do a full system backup to a SMB share over a 100 Mbps ethernet LAN on a dual-core G5.

I've learned that this must be done to a disk image.

BUT

Once the transfer stage begins I get about 1.5 MB/s...

If I point SD! at my 2nd HD to create the image, I get 11 MB/s...

Anyone know what is going on here?

dnanian 12-02-2005 08:25 AM

Sure: things are slower over a network, regardless of the speed of the underlying protocol -- there are far more transport layers doing stuff, and each takes its toll...

simon 12-04-2005 03:18 PM

Sorry Dave I wasn't clear in my post.

The 1.5MB/s speed is only when copying to a disk image that is on the network and mounted locally.

Regular finder copies to the same SMB share go at 6MB/s...

dnanian 12-04-2005 03:22 PM

Yes, I understand. It's indirected even further by the sparse image, so there's some overhead there.

simon 12-05-2005 06:58 AM

does that seed seem correct for a 100 Mbps connection?

I'm waiting for a 1000 Mbps switch to arrive... Should be interesting to see how much it helps...

I know the emphsis with SD! is on cloaning and creating bootable backups, but it seems it would be a good option to allow straight copies over the network.

Why? NAS (networked attached storage) units are growing in popularity and necessity (people with DSLR's and massive mp3 and video collections and multiple computers).

I am using a Infrant Ready NAS X6, which gives me over a terribyte of raid 5 redunancy. This speed hit with Images may make DS! a non-option for me, as I plan to use the X6 to backup all the machines in the office. I can use Rsync, but it's much more of a pain to set up and SD! feature and interface seem really good.

Can we get a check box to allow network copies?

dnanian 12-05-2005 07:50 AM

Sorry, that's not in the plan. Network copies to your NAS won't work, because there's no way to provide a full-fidelity backup, with all ownership and everything else intact in native format.

Using a sparse image allows us to authorize against it (and thus copy files that are owned by a user other than the one logged in), keep HFS+ as the file system, and preserve everything -- metadata, EAs, ACLs, the whole thing -- in a directly accessible Finder format that can roundtrip with no stripping of info.

The fact that there's a speed penalty for doing it that way -- something that will no doubt improve as Apple improves the way the OS manages both network traffic and its own file I/O -- is secondary compared to the above... and since Smart Update is far faster once the main copy is done, and you're typically scheduling a backup to be done when the machine is idle, I don't think that focusing on this is a priority right now.

Hope that explains my position on this...

mikeap 03-16-2006 02:25 PM

Dave,
I too have a Ready NAS network attached storage device. I'd like to use SD to create Sparse Images on this device. Each computer I have has SD, and each could create their own sprase image on the NAS, and then automatically update the image at night, to make up for the slower transfer speed. This would work, correct?
Assuming it will, what happens if my HD dies on a machine and I buy a new HD or machine, how can I clone the sparse image on the NAS to my new drive or machine, so that it is a bootable clone I'm putting on my new drive or machine.
Thanks Dave
Mike

dnanian 03-16-2006 02:31 PM

If you can mount the NAS from Disk Utility when running from your OS install disc, you'd then use File > Open Disk Image... to mount the sparse image, and Disk Utility to restore the resulting volume.

If you can't access it that way, and have no other means of booting, you'll need to copy it to a location that is accessible.

Make sense?


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