test hash functions for fsid

Rick Macklem rmacklem at uoguelph.ca
Wed May 8 23:53:02 UTC 2019


Peter wrote:
>Here’s the output from a couple of our servers (filur00 with around 24289 zfs >filesystems, balur01 with about 72350 zfs filesystems, filur04 about 7500 zfs >filesystems):
>
>
>Lpeter86 at filur00:~ % ./testhash
>H1: max=24290 min=0
>H2: max=24290 min=0
>H3: max=24290 min=0
>H4: max=24290 min=0
>
>Lpeter86 at balur01:~ % /tmp/testhash
>H1: max=73343 min=0
>H2: max=73343 min=0
>H3: max=73343 min=0
>H4: max=73343 min=0
>
>Lpeter86 at filur04:~ % /tmp/testhash
>H1: max=7560 min=0
>H2: max=7560 min=0
>H3: max=7560 min=0
>H4: max=7560 min=0
>
I'll admit when I first looked at this, I was baffled;-)
Turns out the f_fsid field is just zeros when getmntinfo() is run by non-root.
Please do this again as "root". I have attached a slightly modified version
with an additional trivial hash and it calculates variance.

Thanks for doing this, rick

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