On 08/04/2016 07:39 PM, Jens Axboe wrote:
On 08/04/2016 04:53 AM, Srinivasa Chamarthy wrote:
Tried the latest git, i do not get the failure now. But i have the
following questions
1) The initial failure was due to the fact that there were no files in
the directory to read. In that case, it may be expected that we write
the files first and then do read (workload defaults to read if --rw is
not specified).
Right, but that's similar to how a normal read job without
create_on_open would also layout the files to be able to run the read
workload.
2) For Write or mixed jobs, create_on_open is expected not to layout
the IO files before the workload. Currently with the latest git, i see
that it says that files are layed out (but the size is 0) before the
workload starts. If i do not specify create_on_open, its not laying
out files at all. And i have to specify create_on_open=0 explicitly to
layout the files completely.
With create_on_open=1
# fio --name=test --directory=/testdata --nrfiles=10 --size=1g
--refill_buffers=1 --direct=1 --create_on_open=1 --rw=write
test: (g=0): rw=write, bs=4K-4K/4K-4K/4K-4K, ioengine=psync, iodepth=1
fio-2.13-38-gff56
Starting 1 process
test: Laying out IO file(s) (10 file(s) / 0MB)
Jobs: 1 (f=10): [W(1)] [100.0% done] [0KB/5684KB/0KB /s] [0/1421/0
iops] [eta 00m:00s]
Without create_on_open (No Initial layout of files)
# fio --name=test --directory=/testdata --nrfiles=10 --size=1g
--refill_buffers=1 --direct=1 --rw=write
test: (g=0): rw=write, bs=4K-4K/4K-4K/4K-4K, ioengine=psync, iodepth=1
fio-2.13-38-gff56
Starting 1 process
Jobs: 1 (f=10): [W(1)] [8.2% done] [0KB/6612KB/0KB /s] [0/1653/0 iops]
[eta 02m:37s]
With create_on_open=0 (its laying out files)
# fio --name=test --directory=/testdata --nrfiles=10 --size=1g
--refill_buffers=1 --direct=1 --rw=write --create_on_open=0
test: (g=0): rw=write, bs=4K-4K/4K-4K/4K-4K, ioengine=psync, iodepth=1
fio-2.13-38-gff56
Starting 1 process
test: Laying out IO file(s) (10 file(s) / 1023MB)
Jobs: 1 (f=10): [W(1)] [5.1% done] [0KB/6328KB/0KB /s] [0/1582/0 iops]
[eta 02m:49s]
Just wanted to get confirmation on what's the default behavior. I was
under the impression that if create_on_open is not specified, default
behavior is to layout the files for jobs.
Right, that was essentially the behaviour before the recent change. With
the recent change, it'll lay them out if it needs to. It needs to, if
the actual job doesn't do it, or if overwrite=1 is set, for instance,
and it's a writable job.
I have reverted the change, I think the previous behavior made more
sense. I think you alluded to that as well.
--
Jens Axboe
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