On Wednesday 02 February 2005 00:01, Frank Smith wrote:
>--On Tuesday, February 01, 2005 23:42:19 -0500 Gene Heskett
<gene.heskett AT verizon DOT net> wrote:
>> On Tuesday 01 February 2005 18:42, Tom Simons wrote:
>>> Can/should Amanda use an Iomeg REV drive as an output tape?
>>>
>>> We've got 2 servers both running RedHat AS 3.0, with 35gb & 70gb
>>> hard drives on each, and we're intersted in running Amanda on one
>>> of the servers to back up both (& more servers to follow). The
>>> "backup" server has a 35gb Iomega REV drive, which RedHat sees as
>>> /cdrom2.
>>>
>>> Has anyone used a REV drive with Amanda?
>>
>> I can imagine that it may be possible, with some variation of the
>> FILE: device, and as Jon mentioned, they have a 10 disk changer
>> available which to me, would make it *much* more appealing given a
>> reasonable price for both the drive and the media..
>>
>> Jon (or anyone else with some thoughts here) how would one go
>> about dealing with the fact that the Iomega drive is probably a
>> random access drive, meaning it would need to use the FILE:
>> device, *and* treat it as a robotic changer mechanism to bring the
>> proper disk into the drive proper?
>>
>> The first thing would be to investigate and find out if the mtx
>> driver can control the robot.
>>
>> Without the robotics, and just feeding it the disk cartridge by
>> hand, and using the FILE: device, it seems to me that wouldn't be
>> too hard to setup assuming that Tom can build snapshot
>> 2.4.5b1-20041221.tar.gz, obtainable from the amanda.org front page
>> via link near the bottom of the page.
>>
>> Whats the rated read/write speeds on that drive Tom? For amanda
>> to be useable, it needs to be able to do a more or less normal
>> backup in not more than 3-4 hours total elapsed time. Can it fill
>> that sized disk in a reasonable time frame?
>
>Depending on the environment, that might not be a requirement. For
> my work config, I've got plenty of holdingdisk space, and my main
> need is a short backup window, and the time to tape is not really a
> concern (although I don't want it to run ALL day). On my home
> systems I don't really care if it takes all day, as long as it
> finishes. YMMV, of course.
> I realize that many people using vtapes may not be using a
> holding disk due to possible I/O contention issues, but if you are
> using slow 'disks' then perhaps a holdingdisk would make sense.
>
>Frank
While some of that is true no doubt, in my own vtapes, the holding
disk is actually a hair slower than the disk with the vtapes on it,
not by very much though. And I'm still using the holding disk albeit
amanda never gets into it more than 3GB or so as it build up a single
file. Where I seem to be taking it on the shorts so to speak is in
amandas use of gzip, which can bring this XP-2800 Athlon to it knees
begging for mercy for 10 or more minutes at a time.
And this virtual seizure of the cpu doesn't show in a top of htop
report. When the machine is essentially frozen, gzip is getting about
the same amount of cpu that setiathome is getting at a nice 19 at the
exact same time. But on screen response to a character typed in an
editor can get 2 to 3 lines behind my typeing, and I'm certainly no
great shakes at typeing speeds, 10-15 wpm maybe, a well trained hunt
and peck'er if you will.
dma is functioning on all drives here, but another virtual lockup is
when it moves the file from the holding disk /dev/hda, to the vtape
disk, /dev/hdd, there is a few seconds where even the X clock on the
lower right corner can be seen to stutter a bit.
All this is off-topic of course, just tossing it out in case someone
is interested in the anecdotal evidence. :-) The bottom line is with
vtapes, even a backup that makes heavy use of gzip is done about 2
hours faster compared to the 370k/second my old DDS2 tapes could do.
Starting at 1AM, its been known to kick the report out of the printer
by 2:15AM after packing around 12 Gb of stuff into tarballs and
writing them.
--
Cheers, Gene
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
99.32% setiathome rank, not too shabby for a WV hillbilly
Yahoo.com attorneys please note, additions to this message
by Gene Heskett are:
Copyright 2005 by Maurice Eugene Heskett, all rights reserved.
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