On 07/26/2011 07:25 AM, NeilBrown wrote: > On Wed, 20 Jul 2011 19:57:03 +0200 Piergiorgio Sartor > <piergiorgio.sartor@xxxxxxxx> wrote: > >> Hi Neil, >> >> sorry for the very late answer. >> >> On 05/16/2011 12:08 PM, NeilBrown wrote: >>> On Sun, 15 May 2011 23:15:15 +0200 Piergiorgio Sartor >>> <piergiorgio.sartor@xxxxxxxx> wrote: >>> >>>> Hi Neil, >>>> >>>> reminder for the suspend patch. >>>> >>>> Thank you so much for the code review. >>>> >>>> I modified it in order to fix, hopefully, all the flaws. >>>> >>>> New patch attached below. >>>> >>>> Please note that "sigblock()" cannot be used, since it is >>>> declared, at least on my system, as "deprecated". >>>> Furthermore, I noticed that "Grow.c" is not checking the >>>> return value of "sysfs_set_num()" while suspending the >>>> array, maybe you'll need to look at this. >>>> >>>> Finally, please check the new patch too, while I can >>>> confirm the software is doing what is supposed to do, >>>> I still need support in order to confirm the suspend >>>> and resume code. >>>> >>>> Thanks again for your help, again let me know what >>>> is the next expected step. >>> >>> That all looks fine thank. I've applied it and pushed it out. >>> >>> I'm not sure what you mean exactly by the 'next expected step'... >> >> Well, is there anything than should be done, like >> documentation or code cleanup? >> >> At the moment, it seems to me, the check itself it is >> fine, maybe performance is not at best (anyone wants >> to help, here?). >> >> So, I was thinking about the "repair" process, that is >> fixing the chunks which seem corrupted, instead of just >> the parity. >> >> Before I go that way, I would like to close pending issues, >> if any, with the actual software. > > Very sensible - thanks. > > I haven't actually used it or tested it at all so I don't know of any issues > in that regard. > I agree with an earlier reply that a man-page would be a good idea. > You could start by looking at "mdadm.8.in" and basing your man page on that. > It doesn't have to be very long - just explain what it does and how to use > it, and maybe how to interpret the results. > Often writing a man page is enough to flush out any serious usability issues > - if you find it hard to explain how to use it, it is probably because it is > hard to use :-) > > If you aren't familiar with the troff -man markup language don't let it worry > you - I am happy to fix up any markup issues before including it. > > It might be good to create a test script too - something that can go in the > tests/ directory would be ideal. > e.g. create and initialise a RAID6, deliberately corrupt one block, then run > your program an check that it reports the right thing. > Probably corrupt a different blocks (randomly?) on each device and test that > it reports all of the errors correctly... something like that. > > NeilBrown > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html Hi Neil, please find below a draft of the man page (as patch) for raid6check. Please have a look and let me know any issues (typos for sure). The test cases will come later. --- cut here --- diff -uNr a/raid6check.8.in b/raid6check.8.in --- a/raid6check.8.in 1970-01-01 01:00:00.000000000 +0100 +++ b/raid6check.8.in 2011-08-07 19:04:17.352680683 +0200 @@ -0,0 +1,101 @@ +.\" -*- nroff -*- +.\" Copyright Piergiorgio Sartor and others. +.\" This program is free software; you can redistribute it and/or modify +.\" it under the terms of the GNU General Public License as published by +.\" the Free Software Foundation; either version 2 of the License, or +.\" (at your option) any later version. +.\" See file COPYING in distribution for details. +.TH RAID6CHECK 8 "" v1.0.0 +.SH NAME +raid6check \- check MD RAID6 device for errors +.I aka +Linux Software RAID + +.SH SYNOPSIS + +.BI raid6check " <raid6 device> <start stripe> <number of stripes>" + +.SH DESCRIPTION +RAID 6 devices in which one single component drive has errors can use +the double parity in order to find out the component drive. +The "raid6check" tool checks, for each stripe, the double parity +consistency and, it reports mismatches and, if possible, which +component drive has the mismatch. +Since it works at stripe level, it can report different drives with +mismatches at different stripes. + +"raid6check" requires a non-degraded RAID 6 MD device, as first +parameter, a starting stripe, usually 0, and the number of stripes +to be checked. +If this third parameter is also 0, it will check the array up to +the end. + +"raid6check" will start printing information about the RAID 6, then +for each stripe, it will report the parity rotation status. +In case of parity mismatches, "raid6check" reports, if possible, +which component drive could be responsible. Otherwise it reports +that it is not possible to find the component drive. + +If the given MD device is not a RAID 6, "raid6check" will, of +course, not continue. + +If the RAID6 MD device is degraded, "raid6check" will report +an error and it will not proceed further. + +No write operation are performed on the array or the components. +Furthermore, the checked array can be online and in use during +the operation of "raid6check". + +.SH EXAMPLES + +.B " raid6check /dev/md0 0 0" +.br +This will check /dev/md0 from start to end. + +.B " raid6check /dev/md3 0 1" +.br +This will check the first stripe of /dev/md3. + +.B " raid6check /dev/md1 1000 0" +.br +This will check /dev/md1 from stripe 1000 up to the end. + +.B " raid6check /dev/m127 128 256" +.br +This will check 256 stripes of /dev/md127 starting from stripe 128. + +.B " raid6check /dev/md0 0 0 | grep -i error > md0_err.log" +.br +This will check /dev/md0 completely and create a log file only +with errors, if any. + +.SH FILES + +"raid6check" uses directly the component drives as found in /dev. +Furthermore, the sysfs interface is needed in order to find out +the RAID 6 parameters. + +.SH BUGS +Negative parameters can lead to unexpected results. + +It is not clear what will happen if the RAID 6 MD device gets +degraded during the check. + +.PP +The latest version of +.I raid6check +should always be available from +.IP +.B http://www.kernel.org/pub/linux/utils/raid/mdadm/ +.PP +Related man pages: +.PP +.IR mdadm (8) +.IR mdmon (8), +.IR mdadm.conf (5), +.IR md (4). +.PP +.IR raidtab (5), +.IR raid0run (8), +.IR raidstop (8), +.IR mkraid (8). --- cut here --- -- piergiorgio -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
