[CentOS] slow usb hard disk performance.

Tue Dec 6 01:16:12 UTC 2005
William A. Mahaffey III <wam at HiWAAY.net>

Bryan J. Smith wrote:

>"William A. Mahaffey III" <wam at HiWAAY.net> wrote:
>  
>
>>19 GiB in 36 minutes, I wouldn't be complaining either :-).
>>    
>>
>
>It's not bad at all.
>
>  
>
>>I'm using DDS-2 & 3, & they are MUCHO slower ....
>>    
>>
>
>As I mentioned, DDS-2 is 15 years old and a measly 0.8MBps
>native.  DDS-3 is about 10 years old and about 1.6MBps.
>
>Tape is one of those commodities that really require a
>minimum of a $1K investment with something like VXA.  And if
>you really can, it's best to spend $3-4K and go for the gold
>in something like LTO-3 with its 400GB native capacity and
>80MBps transfer rate (double each with hardware compression).
>
>Anything less really isn't worth it.  Especially not at the
>cost of backup cartridges.
>
>  
>
>>I do also backup across my network to a sorta-spare HDD on
>>another box,  but use the DAT tapes for remote storage. 
>>    
>>
>
>Which is what many organization should do.  They should
>guarantee they get some sort of daily backup, which is
>easiest to do with disk.  Especailly when just doing
>sychronization of diffs, which drastically cuts down on
>network usage -- especially during the all important "backup
>window."
>
>It's also easier to restore, easier to do just about
>everything when you have a full copy on random access disk. 
>It is also easier to backup tape, directly, locally and 24x7
>-- no more backup window constraints -- from that server. 
>It's also easier to verify backups against original, when the
>backup server has a local copy -- again, at any time, 24x7,
>not bothering the network.
>
>When I integrated any solution, I always told the client to
>put in 4x the disk they needed, then another 2.5x that size
>(for a total of 14x) for snapshots, disk backup, etc... 
>Ideally this is a separate system, but in the worst case, it
>was just a separate array.  If you're spending $4K on a
>server with such storage, then another $1K on basic tape
>backup is well worth it.
>
>  
>
>>I might need to look into a firewire/USB disk for that 
>>at those speeds :-).
>>    
>>
>
>FireWire is pretty commodity these days on at least AMD
>platforms.  I've had far less headaches with it, as long as
>I'm not running "on-line" data with it.  I never do it with
>FireWire _or_ USB for that matter.
>
>If I need something "on-line," I still use external SCSI LVD.
> SAS will become my preferred favorite soon enough.
>  
>

I'm thinking about adding a DDS4 DAT drive to the box that I am 
currently using for LAN daily backups, kinda like you suggest. Now I 
have a menagerie of boxen backing themselves up & in some cases 
LAN-backing and/or taping others. Quite the hodge-podge solution, but 
reliable enough ....

My backup window is ~12:00 A.M. for the major LAN backup, usually done 
in < 2 hours, then 4:45 A.M. to LAN-back my Win2K box onto an SGI Octane 
(w/ DDS3 drive), then ~6:00 A.M. to whenever-it's-done for various 
tapes, usually once a week, so usually no sweat there. This is a 
private-LAN only, not servers.

-- 
	William A. Mahaffey III
---------------------------------------------------------------------
	Remember, ignorance is bliss, but
	willful ignorance is LIBERALISM !!!!

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