Windows kstat

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Windows kstat[edit]

kstat is the utility used on illumos to query the kernel for various statistics and detailed information. It performs more of less the same responsibly as /proc/ on Linux.

Simply run the command to dump everything:

kstat.exe
(output is large)

You can also use it to set certain tunables in the kernel, for example:

Arc Max[edit]

It is now recommended that you use the Registry to set the ZFS tunables.

To set max ARC size to 512 MiB:
kstat.exe -w zfs:0:tunable:zfs_arc_max=536870912

Dump the "zfs:0:tunable" sub-section to list the available knobs to fiddle with.

A setting is not retained over reboot, and will need to be set each boot. (In the future, there will be something to handle this automatically)

HostID[edit]

The HostID on Windows is generated from the Software/Microsoft/Cryptography/MachineGuid and generally most users do not need to change it. However, should you want to set the HostID that ZFS uses, you can do so by running;

 kstat.exe -w zfs:0:tunable:hw_hostid=11223344

ZFSin debug[edit]

You can also ask the kernel to save the debug print buffer to disk.

 kstat.exe -w zfs:0:tunable:vnop_debug=1337

Will write the buffer to C:/Windows/debug/ZFSin.txt - if the directory exists.

See Debug for more information on the debug buffer.