On Thu, Jul 20, 2006 at 03:55:02PM -0400, Sean Walmsley wrote:
> This post documents our experience with the version 2.5.0p2 tape spanning
> option in the hopes that someone has suggestions for getting it working
> acceptably. Even a "me too" would be useful information.
> 
> System info:
> ============
> Solaris 8 (sparc) 64-bit
> SunFire V880 (4-way) with 8Gb of memory
> Amanda 2.5.0p2 compiled as a 32-bit executable using gcc 3.4.5
> SDLT 600 tape robot (~400Gb per tape x 13 tapes)
> 4 individual 36Gb holding disks
> most DLE's ~ 36Gb to ~72Gb, total ~300Gb
> 2 large DLE's of ~500Gb each

This is just a "me-too" comment.
I started a thread on amanda-hackers "mmap problems in tape spanning".

One thing I don't see in your very nicely detailed note is a mention
of defining a split_diskbuffer.  This disk buffering could be used
like a holding disk but eliminates the need for it to hold the entire 
dump.

My environment is a bit smaller, a 1-way PIII with 0.5GB of memory :)
But I have more holding disk than you (stick my tongue out ;)

I have no problems with tape spanning when the holding disks
are in use, and no situations that should call for them to not
be used.

But I decided to explore some limits.  So I turned off the holding
disk by putting in "holdingdisk no" in the dumptype.  The results were
basically, when my system tries to use mmap, I get errors if my
tape_splitsize and/or fallback_splitsize are greater than 100MB.
Even 128MB gives me "cannot allocate memory" errors in the mmap call.

-- 
Jon H. LaBadie                  jon AT jgcomp DOT com
 JG Computing
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