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Re: tapetape (not in faq-o-matic)
2006-05-23 16:45:47
On Tue, 23 May 2006 at 3:55pm, Brian Cuttler wrote
Does anyone have the tape type for the LTO3 (Quantum) ?
This is what I use:
define tapetype LTO3comp {
# All values guesswork :) jlb, 8/31/05
# except blocksize ;) jlb, 9/15/05
length 420000 mbytes
blocksize 2048
filemark 5577 kbytes
speed 60000 kps
lbl-templ "3hole.ps"
}
I leave hardware compression on (why not, with LTO), but most of my data
isn't all that compressible. I get much better speed with the blocksize
above (2MiB) rather than amanda's default of 64K. I determined that by
testing raw write speed to the tape with tar and various blocksizes.
Are there any other parameters I should tweak to get better
performance/utilization ?
This is still a reasonable default ?
tapebufs 20
On Linux at least, with the blocksize above I had to dial back tapebufs to
15 or I got this warning in my nightly emails:
taper: attach_buffers: (20 tapebufs: 41947616 bytes) Invalid argument
taper: attach_buffers: (19 tapebufs: 39850440 bytes) Invalid argument
taper: attach_buffers: (18 tapebufs: 37753264 bytes) Invalid argument
taper: attach_buffers: (17 tapebufs: 35656088 bytes) Invalid argument
taper: attach_buffers: (16 tapebufs: 33558912 bytes) Invalid argument
I am running the StorEdge C2 jukebox with lto3 drive on a SunFire 280R
under Solaris 9 with 4 gig of memory.
My usual warning with LTO3 is to make sure that your disks can keep up
with your tape. Yes, you read that right. Especially with amanda dumping
to holding disk while trying to write to tape, it's tough to feed LTO3 as
fast as it wants to be fed (80MB/s native write speed). LTO3 can throttle
back to half that without shoeshining the drive, but you don't want to see
your write speeds below that.
--
Joshua Baker-LePain
Department of Biomedical Engineering
Duke University
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