Re: Is 1.5MB/min toooo sloow?

1999-12-21 Thread Ryan La Riviere

On 12/21/1999 somewhere around the time of 19:07 +1300, Owen Watson spoke about "Is 
1.5MB/min t sloow?":


I've got a 90MHz Pentium on the network that seems to get only 1.5MB/min backup rate 
as a remote client. Is this about par for the course? Any suggestions if there are 
problems?
.

Depends on the network, the tape drive being backed up to/computer doing the backing 
up and what the P90 is doing or if it has any screwy network settings.  1.5 MB/min 
seems a little slow but that may be what your setup does.  I don't have any machines 
that slow being backed up but for comparison I have a PII 366 over 10BT backed up to a 
Sony DDS-3 SDT9000 and I get about 24 MB/min.  I figure anything below 12-15 MB/min 
and you should be looking around to see where the bottleneck is.  I have another 
machine, P150, that gets about 13 MB/min across the same network to the same drive but 
the I know the bottleneck is the part of the network it is on (it's dirt slow 
(sub-Localtalk speed)).  That will be fixed once the 100BT network is up and running 
and I should see a dramatic speed increase for that machine.  The limitation will then 
become the tape drive.  When I compare speeds for the DDS-3 drive and a the DDS drive, 
there is a great speed difference.  I don't remember what the speed is that I get for 
the DDS drive.

I'd start looking.

Hope this gives you some sort of direction.  It's 3 am and I'm a little groggy.
-- 

Ryan La Riviere

Lab Services Coordinator; Drexel University
215.895.6010
ICQ: 11747071, 44292959
http://iae-tech.coe.drexel.edu/larz


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Re: during retrospect rewind the tape...

1999-12-21 Thread David Ross

Actually this allows me to attach the tape drive to the power plug on
the back of the CPU so it shuts down with the system. Without the wait
it will power it off DURING the rewind.

Thomas Myers wrote:
 
 This is a good example of when to use the asynchronous scsi calls. While the call 
completes you can be doing waitnextevent so the computer is not FROZE during this 
time. (Which can be over 1 minute for some media!)
 
 Tom
 
  Reply to:   RE: during retrospect rewind the tape...
 Oops! That last paragraph was wrong. What I meant to say was...
 
  The reason it takes so long? My guess is that Retrospect is waiting
 until
  the command that it sent to the tape drive (to REWIND) has completed
  before freeing up the machine for other tasks.
 
 Sorry folks,


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Re: using large hard disk as backup destination

1999-12-21 Thread Jim Coefield

This is what we do in our GIS lab. We automatically duplicate 
(nightly when no ones working and files are closed) many drives that 
contain our critical ArcView and ArcInfo data scattered across our 
network (combination Windows 95, 98, NT4) to a single map server 
(NT4) via Retro on a Mac (100base-T ethernet) that has several 27 GB 
hard drives. You just need to make sure that the subvolumes you 
create on the destination drives, representing the drives scattered 
across the network, contain enough free space.

The map server w/backup drives then gets backed up periodically to 
tape. This situation seems to keep our map techs happy, as they worry 
about data integrity once the GIS info has been written to tape, 
given Arc's unique handling of data structures, pointers, and 
workspaces. Restores for Arc GIS data have to be done very carefully, 
and being able to move data from a duplicated drive back to its 
original location is much preferred to restoring from tape. Took one 
Arc workstation meltdown, wrestling with the Arc data structure to 
devise this (hopefully) foolproof system.

One gotcha on many PC machines: the BIOS can't handle drives larger 
than, I believe 32GB without being upgraded. Not all PCs will allow 
you to upgrade their BIOS, or it isn't worth the time and effort to 
do so. Found out the hard way, which is why my BW G3 has a nice 34GB 
Maxtor (which had a disclaimer "inside" the box about this possible 
limitation), and the PC has 27GB drives. Not often you can one-up the 
PC/NT support person, when you're the Mac guy in the lab. But in this 
situation with Retrospect, you sure can.

Jim Coefield
[EMAIL PROTECTED]

 


Subject: Re: using large hard disk as backup desitination
From: "Erik Ableson" [EMAIL PROTECTED]
Date: Mon, 20 Dec 1999 17:42:55 -0500

Hmmm - here's an alternate possibility:

1.  Set up a folder for each client volume to be backed up
2.  Set each folder as a volume using the subvolume option in Retrospect
3.  Create a duplicate script for each of these.  Using the duplicate
function with replace entire HD, you will get a mirror of each volume on
the server - retrospect is smart enough to do an incremental duplicate
so these should run pretty quickly
4.  Then backup the server locally to a handy tape device.

This will require more active management and tracking as you won't be able
to use Retrospect's advanced search features by client name since it will
all be one data source, but if you organize your server structure carefully,
you should be OK.  You also won't be able to use the smarts of the backup
server scripts and will be stuck with scheduled ones (not critical for a
smaller backup group tho').

Cheers,

Erik Ableson

NB - this only works if you have a clear controlled client group that you
know exactly the available capacity and can ensure that you have sufficient
space on the server.

Ancillary issues are that if you have a mix of Windows and Mac clients there
are some naming issues that may arise since the Mac can't handle names over
32 characters, and if you decide to try this from a Windows box, you'll need
to ensure that you have things set up to properly handle MacOS resource
forks. Sigh - nothing's ever as simple as it first looks.



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