Amanda-Users

Re: amtapetype idea (Was: Testing tapes before use / bad tape)

2003-11-24 18:55:29
Subject: Re: amtapetype idea (Was: Testing tapes before use / bad tape)
From: Eric Siegerman <erics AT telepres DOT com>
To: amanda-users AT amanda DOT org
Date: Mon, 24 Nov 2003 18:51:42 -0500
On Mon, Nov 24, 2003 at 07:14:56PM +0100, Paul Bijnens wrote:
> My idea was to write only one large file in the first pass, just
> until [amtapetype] hits end of tape.

One problem with that is that the drive's internal buffering
might distort the results, by letting amtapetype think it has
successfully written blocks that in fact won't make it to tape.
(That's a problem anyway, of course, but sticking in a filemark
every once in a while puts a known upper bound on the error.)

Perhaps amtapetype could have a "test-tape" flag, that would
basically tell it to suppress the second pass.  Or the second
pass could become a verification pass (just re-seed the
random-number generator to the value from the beginning of the
write pass).  Or provide both options.

Of course that would make "amtapetype" a rather misleading name.
"amtape" would be a great choice for a new name; too bad it's
taken :-/

--

|  | /\
|-_|/  >   Eric Siegerman, Toronto, Ont.        erics AT telepres DOT com
|  |  /
It must be said that they would have sounded better if the singer
wouldn't throw his fellow band members to the ground and toss the
drum kit around during songs.
        - Patrick Lenneau