----- Original Message -----
From: "Matthew Ahrens" <[email protected]>
Please use an enum for vdev_rotation_state
There's no such variable, are you refering to vdev_rotation_rate?
yes
If so this was initially a bool for non-rotating but it was deemed using
rotation_rate would be more helpful moving forward, as this value could
be used to make more intelligent decisions.
Yes, changing it to a bool would probably be even better. Going forward,
it will be easy to change this to a different type when necessary.
I'd prefer to keep it as the actual rate not an enum or bool so if we
look to make improvements in the future we have rotation rate of the
device and dont have to implement yet another struct member to store
this.
An example of this could be calculate lower loads for vdevs with a higher
rotational rate.
To clarify as per ATA and SCSI specs:
0 = Rate unknown
1 = Rate non-rotationl
2-INT16_MAX = rotational rate
vdev_mirror.c:
unfortunately I think we have to declare tunables as non-static, otherwise
gcc can optimize them away. perhaps prefix the variable names with
"zfs_mirror_"?
These are tunables in FreeBSD and Linux does illumos have such things?
yes, they can be set by /etc/system or mdb.
If cc optimises them away is that an issue?
yes, because then they can't be tuned.
Ah so you can poke those values directly using /etc/system and you
dont need any special handlers like sysctl in FreeBSD?
138: I don't understand this comment, or what code it is referring to; can
you elaborate? I don't see any check for resilvering before returning
UINT_MAX above.
In a previous revision INT_MAX was returned if vdev_resliver_txg != 0
as it was assumed that avoiding the device that was reslivering would
improve performance. Justin found this assumption didn't hold true, hence
the early return was removed and the comment added so others are aware of
this in case they thought of the same thing.
So you'll remove the comment?
I'm a little confused, its not my current intention to remove the comment
as removing it wouldn't allow someone looking at the code to know this had
be tried and it doesn't help. Does that make sense?
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