Hi,
I wanted to check out the following issue that was brought up in one of the responses to my poll (still waiting for more replies):
When a TLU (tape Library Unit) is directly attached to a fileserver, does every reboot of the TLU necesarily mean you must reboot the fileserver?
OR
Is this only specific to the TLU vendor ( as suggested below).
I see this as a serious issue!! I don't want the uptime of my fileserver to be affected by something like this.
Manny Kaiser Email : mannyk@msil.sps.mot.com Unix System Administrator Phone : 972-9-9522-603 Motorola Semiconductor Israel LTD. Fax : 972-9-9562-990
1 Shenkar St. Industrial Zone Herzelia Herzelia 46120 Israel =============================================================================
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From alexei@cancerman.cimedia.com Thu Apr 23 07:31:50 1998 Received: from cancerman.cimedia.com (nat-a-29.cimedia.com) by spsgate.sps.mot.com (4.1/SMI-4.1/Email 2.1 10/25/93)
id AA22939 for mannyk@msil.sps.mot.com; Wed, 22 Apr 98 21:26:58 MST To: Menachem Kaiser (Manny) mannyk@msil.sps.mot.com Subject: Re: backup and Restore questions Date: Thu, 23 Apr 1998 00:27:08 -0400 From: Alexei Rodriguez alexei@cimedia.com
+--- In a previous state of mind, Menachem (Manny) Kaiser <mannyk@msil.sps.mo t.com> wrote: | | First many thanks for participating in this poll.
No problem. My pleasure.
| Why do you backup using only one stream of data.
Actually, that may not be accurate. I think we break all the file systems into chunks and work on single chunks at a time. The main reason that we run a single stream (I need to verify) is that with one drive we did not gain too much. That may be incorrect.
| Is this just a problem with your backup software?
Don't know. I'll have to ask the backup person. Might be related to our installation.
| You mentioned a very interesting note - attaching a jukebox | to the fileserver might mean that you will need to reboot the file | server from time to time. WHY? | When you reboot the tape library juke box - does this force | you to reboot the file server as well?
If the stacker/jukebox hangs for whatever reason (robotic arm, etc), and you need to power-cycle the tape device, you cannot do so with the filer on. You run the risk of frying the scsi bus.
Now, it could be that the problems I had were related to the specific DLT stacker (an ADIC vls library) we used. I don't know. I have not risked that sort of problem any more.
Alexei
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At 08:31 AM 4/23/98 +0300, Manny wrote:
When a TLU (tape Library Unit) is directly attached to a fileserver, does every reboot of the TLU necesarily mean you must reboot the fileserver? OR Is this only specific to the TLU vendor ( as suggested below).
Hot swapping anything on a SCSI bus is "not supported" but will work 90+% of the time.
In other words, it'll almost always work, but on the most critical time when you really can't afford any down time, you'll be mucking with a SCSI bus at just the wrong moment and Bad Things Will Happen.
I hot swap SCSI things on non-production systems all the time because I'm lazy, but if I'm going to be in big trouble if the thing fries, I take the time to schedule proper downtime. If a filer fried, I'd be in big trouble, so I don't hot swap SCSI stuff on it.
Amy
ps. I may have confused terms--You can certainly hot swap anything designed for hot swapping, such as disks in the more recent filers. I'm talking about the SCSI bus that's directly attached to the filer itself, and which is not designed for hot swapping, at least not in any filers I've seen.
-
Amy Chused -
Menachem Kaiser