> On Nov 28, 2018, at 12:58 PM, Chris Nighswonger
> <[email protected]> wrote:
>
> On Wed, Nov 28, 2018 at 11:17 AM Austin S. Hemmelgarn <[email protected]>
> wrote:
> Based on your configuration, your tapes are configured to store just
> short of 800GB of data.
>
> The relevant lines then are these two:
>
> flush-threshold-scheduled 50
> flush-threshold-dumped 50
>
>
> I misunderstood the man pages there and for some reason thought that volume
> referred to the holding disk. Probably because I was reading way too fast....
>
> In your case, I'd suggest figuring out the average amount of data you
> dump each run, and then configuring things to start flushing when about
> half that much data has been dumped. That will still have the taping
> run in parallel with the dumping, but will give you enough of a buffer
> that the taper should never have to wait for dumps to finish.
>
> So over the last 13 runs, the:
>
> -- smallest volume size has been 152G (19% tape capacity)
> -- average volume size has been 254G (32% tape capacity)
> -- largest volume size has been 612G (76% tape capacity)
>
> So do the following values look "reasonable" based on those numbers:
>
> flush-threshold-scheduled 25
> flush-threshold-dumped 0
>
> That should target the larger sizes which are the ones which tend to lap into
> the next business day.
>
> Kind regards,
> Chris
Not sure if these paragraphs are still in the example config files or not;
I’ve hung onto them because they
were so useful. In case they help you:
## with LTO5 tapes, as of 2/27/2015, I still only USE one tape.
## Don't faff around; just write to the silly tape. But to avoid
## shoe shining, let some amount accumulate. Else we'd be writing
## the first tiny file and then waiting .....
## Do I even HAVE 20% of a tape's full, on a daily basis? NO!!
## On a normal Thursday 2/27/15 I had 153G of data on spool before
## any writing occurred. (Since I was at that point accumulating all
## on disk before allowing writing to start.) That might only be
## 10% of an LTO5 tape, at a guess. 1450G is what we measured with
## amtapetype, below under the LTO5mine definition.
## 153G is less than 10% of that.
## OK -- set to 5% ??
#flush-threshold-dumped 05 #Default: 0.
# Amanda will not begin writing data to a new tape
volume
# until the amount of data on the holding disk is at
least this percentage
# of the volume size. The idea is to accumulate a
bunch of files,
# so the fill algorithm "Greedy Algorithm" has some
choices to work with.
# The value of this parameter may not exceed than that
of the
# flush-threshold-scheduled parameter.
flush-threshold-scheduled 05 #Default: 0.
# Amanda will not begin writing data to a new volume
until the sum of
# the amount of data on the holding disk and the
estimated amount of data
# remaining to be dumped during this run is at least
this percentage of
# the volume size.
# The value of this parameter may not be less than
that of the
# flush-threshold-dumped or taperflush parameters.
taperflush 0 # Default: 0.
# At the end of a run, Amanda will start a new tape to
flush remaining data
# if there is more data on the holding disk at the end
of a run than this
# setting allows; the amount is specified as a
percentage of the capacity
# of a single volume.
#### dsbdsb ie. 0 == start a new tape if any data
is still on holding disk.
#### Good.
## taperflush <= flush-threshold-scheduled
## flush-threshold-dumped <= flush-threshold-scheduled
#autoflush yes # only flushes those NAMED on the command line. Use
ALL. 6/28/13
autoflush all # flush leftovers from a crash, or a ran-out-of-tape
condition
## further explanatory comments:
#====================================================#
# New amanda includes these explanatory paragraphs:
# flush-threshold-dumped, flush-threshold-scheduled, taperflush, and autoflush
# are used to control tape utilization. See the amanda.conf (5) manpage for
# details on how they work. Taping will not start until all criteria are
# satisfied. Here are some examples:
#
# You want to fill tapes completely even in the case of failed dumps, and
# don't care if some dumps are left on the holding disk after a run:
# flush-threshold-dumped 100 # (or more)
# flush-threshold-scheduled 100 # (or more)
# taperflush 100
# autoflush yes
#
# You want to improve tape performance by waiting for a complete tape of data
# before writing anything. However, all dumps will be flushed; none will
# be left on the holding disk.
# flush-threshold-dumped 100 # (or more)
# flush-threshold-scheduled 100 # (or more)
# taperflush 0
#
# You don't want to use a new tape for every run, but want to start writing
# to tape as soon as possible:
# flush-threshold-dumped 0 # (or more)
# flush-threshold-scheduled 100 # (or more)
# taperflush 100
# autoflush yes
# maxdumpsize 100k # amount of data to dump each run; see above.
#
# You want to keep the most recent dumps on holding disk, for faster recovery.
# Older dumps will be rotated to tape during each run.
# flush-threshold-dumped 300 # (or more)
# flush-threshold-scheduled 300 # (or more)
# taperflush 300
# autoflush yes
#
# Defaults:
# (no restrictions; flush to tape immediately; don't flush old dumps.)
#flush-threshold-dumped 0
#flush-threshold-scheduled 0
#taperflush 0
#autoflush no
#
#====================================================#
Deb Baddorf
Fermilab
