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Slow Macintosh Client Backup Speed


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We are using Retrospect Multi-Server in several similar environments. All the networks that we use Retrospect on are basically Fast Ethernet, with Fast Ethernet / Gigabit switches on the backbone.

 

Retrospect Multi-Server was originally running in version 6.0. An upgrade to 6.5 brought all the desired advantages. Backup speeds for Windows and Macintosh clients (both servers and workstations) leveled out at 400-500MB/min.; some really fast Windows servers even delivered close to 900MB/min., which I found quite impressive.

 

Now, with the upate to Retrospect 7, and recently to 7.5 I found that the backup speed for the Macs had radically dropped, while the backup speed for Windows clients improved by about a third.

I updated all Retrospect clients (7.5.1.1.6 on Windows and 6.1.130 on OS X, which I think is the latest), yet the Macs rarely deliver 50MB/min., most of the time crouching around at <20MB/min.

 

As the Macs (Dual G5s) are all equipped with GB cards I schlepped them over to the server room and connected them to the same managed GB-switch that the backup server is on (using Cat6-cable of course).

The backup server is running a GB-card too. Still, no improvement. Currently I see Retrospect backing up a Macintosh at 17.6MB/min.

I have tried both backup to tape and backup to disk, yet the result stays the same.

 

I'm befuddled, to say the least smile.gif Please throw any questions and suggestions at me; I'll try them in our lab and let you know what happens.

 

Cheers,

Karsten

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  • 2 weeks later...

or, in Terminal on the Macs, the command:

ifconfig

 

look at the line that begins "media:" for the ethernet interface (en0).

 

Using Retrospect Mac, I typically see about 120 to 125 MB/sec over 100BaseT duplex even for relatively slow G3 iMacs through our Netgear FS726T switch. Local backup on our Xserve G5 is always > 400 MB/sec.

 

russ

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Are you guys really reading/telling us the right numbers here?

 

Quote:

some really fast Windows servers even delivered close to 900MB/min., which I found quite impressive.

 


 

900 MB/min works out 15 megabytes per second. That's faster the physical limit of 100 BaseT and we're not even taking into account the overhead.

 

Quote:

120 to 125 MB/sec over 100BaseT duplex even for relatively slow G3 iMacs through our Netgear FS726T switch. Local backup on our Xserve G5 is always > 400 MB/sec.

 


 

I've just got to believe you mean minutes, not seconds.

 

 

Quote:

yet the Macs rarely deliver 50MB/min., most of the time crouching around at <20MB/min.

 


 

The most likely explanation for these (believable wink.gif) values is the duplex setting is wrong. Check ifconfig -a in the command line of the Macs and see what it says for the duplex setting. It's probably at half-duplex. It should be full-duplex

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