[NTLUG:Discuss] NFS & Mirrordir times

[David Venable]

Jack Snodgrass wrote:

>On Wed, 16 Jul 2003 10:46:15 -0500, David Simmons wrote:
>
>  
>
>>(if you've been following - I've got two machines connected through NFS that
>>I want to backup to each other).
>>
>>Through a VPN link with NFS mounted drives - I've had an interesting
>>experience that I was hoping someone could help/improve.
>>
>>I've got two (approx) 3.5 partitions that I was backing up between systems.
>>Using MirrorDir - it took quite awhile to 'mirror/copy' the first.  As a
>>test, I created a file on the original server "test.txt" and stuck it deep
>>in the directory tree - then started the mirrordir command again.  Here's
>>the interesting results:
>>
>>Time to complete the 'syncing' to find new extra file:
>>
>>real		521m40.055s
>>user		0m1.390s
>>sys		0m14.200s
>>
>>Now - time to complete the copying of the second 3.5G of data to create base
>>copy:
>>
>>real		754m48.996s
>>user		0m2.280s
>>sys		1m40.100s
>>
>>Here's my mount command:
>>
>>mount 192.168.1.200:/var/DIRECTORY /mnt/OTHER_DIRECTORY -t nfs -o
>>ro,rsize=8192,wsize=8192,noatime,sync
>>
>>I've included 'noatime' and increased rsize & wsizes....is the 'sync' option
>>what's causing the lengthy times just to read through the directory - or is
>>that 'just as fast as it goes'(tm).
>>
>>BTW.  Am on DSL with 1.5 down/768 up
>>
>>Any ideas for optimization?
>>
>>Thanks in advance - Dave
>>    
>>
>
>
>I've not been following....  have you looked at using rsync at all? I've
>used both NFS and rsync to backup stuff accross the network and most of 
>my test have shown rsync being faster. It might depend on the type of 
>data and amount, but it works better for me. 
>
>Rsync ( in theory ) copies just the changed data in a file. So... if 
>you have a 10meg file that 1000 bytes change in, rsync will only copy
>the 1000+some-overhead-bytes instead of the hole 10meg file. 
>
>Anyway... before you pull your hair out with NFS... you might want to 
>look at other options. 
>
>jack 
>
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>  
>
And rsync can be configured to work over ssh so there's some added 
protection, not to mention being able to compress the SSH connection

Dave