[email protected] (Tinker), 2016.02.20 (Sat) 16:43 (CET):
> On 2016-02-20 22:23, Marcus MERIGHI wrote:
> >[email protected] (Tinker), 2016.02.20 (Sat) 15:29 (CET):
> >>This email is an attempt to get some knowledge on how softraid works.
> >
> >So many of your questions are answered if you start with bioctl(8)[1],
> >and continue with softraid(4)[2]. Maybe bio(4)[3] helps, too.
> >
> >What's there is usually documented. What's not documented is usually not
> >there. Or was it the other way around? ;-)
> >
> >[1]http://www.openbsd.org/cgi-bin/man.cgi/OpenBSD-current/man8/bioctl.8
> >[2]http://www.openbsd.org/cgi-bin/man.cgi/OpenBSD-current/man4/softraid.4
> >[3]http://www.openbsd.org/cgi-bin/man.cgi/OpenBSD-current/man4/bio.4
> >
> >Happy reading, Marcus
>
> Marcus, I read the docs carefully, and based on them, my best
> understanding is still unclear on all 4 points -
>
> * Scrub - MAYBE??? There's some words about "patrol" in the man page that
> could mean it's there.
You appear to mean bioctl(8). Thats the only place I could find the word
'patrol'. bioctl(8) can control more than softraid(4) devices.
bio(4):
The following device drivers register with bio for volume
management:
ami(4) American Megatrends Inc. MegaRAID
PATA/SATA/SCSI RAID controller
arc(4) Areca Technology Corporation SAS/SATA RAID
controller
cac(4) Compaq Smart Array 2/3/4 SCSI RAID controller
ciss(4) Compaq Smart Array SAS/SATA/SCSI RAID
controller
ips(4) IBM SATA/SCSI ServeRAID controller
mfi(4) LSI Logic & Dell MegaRAID SAS RAID controller
mpi(4) LSI Logic Fusion-MPT Message Passing Interface
mpii(4) LSI Logic Fusion-MPT Message Passing Interface
II
softraid(4) Software RAID
It is talking about controlling a HW raid controller, in that 'patrol'
paragraph, isn't it?
> * Rebuild - I think I saw some console dump of the status of a rebuild
> process on the net, so MAYBE or NO..?
That's what it looks like:
$ doas bioctl softraid0
Volume Status Size Device
softraid0 0 Rebuild 12002360033280 sd6 RAID5 35% done
0 Rebuild 4000786726912 0:0.0 noencl <sd2a>
1 Online 4000786726912 0:1.0 noencl <sd3a>
2 Online 4000786726912 0:2.0 noencl <sd4a>
3 Online 4000786726912 0:3.0 noencl <sd5a>
> * Hotspare - MAYBE, "man softraid" says "Currently there is no automated
> mechanism to recover from failed disks.", but that is not so specific
> wording, and I think I read a hint somewhere that there is hotspare
> functionality.
bioctl(8)
-H channel:target[.lun]
If the device at channel:target[.lun] is currently marked
``Unused'', promote it to being a ``Hot Spare''.
That's the only mention of 'hot spare'. And again talking about
controlling a hardware RAID controller, isn't it?
What is 'not so specific' about 'no' (as in "Currently there is *no*
automated mechanism to recover from failed disks")?
> * Hotswap - MAYBE, this would depend on if there's rebuild. Only disconnect
> ("bioctl -O" I think; "bioctl -d" is to.. unmount or self-destruct a
> softraid?)
bioctl -O should fail the chunk specified, simulating hardware failure.
After this command you have an 'Offline' chunk in the 'bioctl' output.
bioctl -d 'detach', not 'destroy'; just as sdX appears when you assamble
a softraid volume, this makes it go away. better unmount before...
> The man pages are sometimes over-minimalistic with respect to an individual
> user who's trying to learn, this is why I'm asking for your clarification.
I am quite sure the man pages are kept as condensed as they are on
purpose.
You can always read mplayer(1) if you want something lengthy ;-)
> So your clarifications would still be much appreciated.
Nothing authoritative from me!
I am just trying to flatten your learning curve.
Bye, Marcus
