ZFS send progress reporting in process title

Discussion:

Xin Li

2013-11-20 02:26:52 UTC

Hi,

This is a proof-of-concept changeset that adds progress reporting via
process title. This is useful for third party observers (for
instance, Web based GUI) to find out what the 'zfs send' process is doing.

Note that this do not yet work for Illumos or Linux due to the lack of
setproctitle(), but it's pretty straightforward to port it to Linux if
the zfs(1) program is linked against libbsd or use compatibility shims
from OpenSSH.

When applied, on FreeBSD, it's now possible to determine the progress
using "top -a" or ps -aux without having a helper program to parse and
process output from "zfs send -v". The progress indicator would look
like this:

zfs: sending tank/home/***@trans01 (80%: 135388948744/168379989120)

Known caveats:

- the "-V" flag is arbitrarily picked, there may be a better form for
that.
- The estimated stream size is slightly smaller than the actual size.
This version capped the percentage value at 100%.

Cheers,

Schlacta, Christ

2013-11-20 02:36:28 UTC

Permalink

I like this idea. The only two suggestions I have are:
1) use -T for title
2) overestimate instead of underestimate. Better to finish early than late
almost always.

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Hash: SHA512
Hi,
This is a proof-of-concept changeset that adds progress reporting via
process title. This is useful for third party observers (for
instance, Web based GUI) to find out what the 'zfs send' process is doing.
Note that this do not yet work for Illumos or Linux due to the lack of
setproctitle(), but it's pretty straightforward to port it to Linux if
the zfs(1) program is linked against libbsd or use compatibility shims
from OpenSSH.
When applied, on FreeBSD, it's now possible to determine the progress
using "top -a" or ps -aux without having a helper program to parse and
process output from "zfs send -v". The progress indicator would look
- the "-V" flag is arbitrarily picked, there may be a better form for
that.
- The estimated stream size is slightly smaller than the actual size.
This version capped the percentage value at 100%.
Cheers,
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Matthew Ahrens

2013-11-20 05:59:03 UTC

Permalink

This is a great achievement for one day's work at the OpenZFS Developer
Summit hackathon!

It looks like you are changing the behavior of -v so that it doesn't print
the size or progress any more? I think we should be cautious about
changing existing behavior. What would you think about keeping the -v
behavior, but adding the -V (or -T, as Christ suggested) behavior in
addition?

--matt