[CentOS] Re: mdadm --stop

Tue Nov 6 21:08:07 UTC 2007
Art Baldini <rootajb at gmail.com>

What version are you using, I do not see that in either version of man
page for mine.

# rpm -qi mdadm
Name        : mdadm                        Relocations: (not relocatable)
Version     : 1.12.0                            Vendor: CentOS
Release     : 2                             Build Date: Thu 03 May
2007 01:30:01 PM EDT
...

On Nov 6, 2007 4:01 PM, Scott Silva <ssilva at sgvwater.com> wrote:
> on 11/6/2007 12:40 PM Art Baldini spake the following:
> > Scott, thanks, that worked.  Is this different from the previous
> > behavior?  I am setting up a system with the old version of mdadm I
> > was using to test this, but I am fairly sure this used to work for me.
> >
> > ...Art
> >
> AFAIR this is the norm. Look at the manpage on the old system if you want to
> verify. That line I quoted is not very far from the top.
>
> <quote>
>
> Name
> mdadm - manage MD devices aka Linux Software Raid.
> Synopsis
>
> mdadm[mode] <raiddevice> [options] <component-devices>
> Description
> RAID devices are virtual devices created from two or more real block devices.
> This allows multiple devices (typically disk drives or partitions there-of) to
> be combined into a single device to hold (for example) a single filesystem.
> Some RAID levels include redundancy and so can survive some degree of device
> failure.
>
> Linux Software RAID devices are implemented through the md (Multiple Devices)
> device driver.
>
> Currently, Linux supports LINEAR md devices, RAID0 (striping), RAID1
> (mirroring), RAID4, RAID5, RAID6, RAID10, MULTIPATH, and FAULTY.
>
> MULTIPATH is not a Software RAID mechanism, but does involve multiple devices.
> For MULTIPATH each device is a path to one common physical storage device.
>
> FAULTY is also not true RAID, and it only involves one device. It provides a
> layer over a true device that can be used to inject faults.
> Modes
> mdadm has 7 major modes of operation:
>
> Assemble
>      Assemble the parts of a previously created array into an active array.
> Components can be explicitly given or can be searched for. mdadm checks that
> the components do form a bona fide array, and can, on request, fiddle
> superblock information so as to assemble a faulty array.
> Build
>      Build an array that doesn't have per-device superblocks. For these sorts
> of arrays, mdadm cannot differentiate between initial creation and subsequent
> assembly of an array. It also cannot perform any checks that appropriate
> devices have been requested. Because of this, the Build mode should only be
> used together with a complete understanding of what you are doing.
> Create
>      Create a new array with per-device superblocks.
> Follow or Monitor
>      Monitor one or more md devices and act on any state changes. This is only
> meaningful for raid1, 4, 5, 6, 10 or multipath arrays as only these have
> interesting state. raid0 or linear never have missing, spare, or failed
> drives, so there is nothing to monitor.
> Grow
>      Grow (or shrink) an array, or otherwise reshape it in some way. Currently
> supported growth options including changing the active size of component
> devices in RAID level 1/4/5/6 and changing the number of active devices in RAID1.
> Manage
>      This is for doing things to specific components of an array such as
> adding new spares and removing faulty devices.
> Misc
>      This is an 'everything else' mode that supports operations on active
> arrays, operations on component devices such as erasing old superblocks, and
> information gathering operations.
>
> Options
> Options for selecting a mode are:
>
> -A, --assemble
>      Assemble a pre-existing array.
> -B, --build
>      Build a legacy array without superblocks.
> -C, --create
>      Create a new array.
> -F, --follow, --monitor
>      Select Monitor mode.
> -G, --grow
>      Change the size or shape of an active array.
>
> If a device is given before any options, or if the first option is --add,
> --fail, or --remove, then the MANAGE mode is assume. Anything other than these
> will cause the Misc mode to be assumed.
> Options that are not mode-specific are:
>
> </quote>
>
>
> on 11/6/2007 12:40 PM Art Baldini spake the following:
>
> > Scott, thanks, that worked.  Is this different from the previous
> > behavior?  I am setting up a system with the old version of mdadm I
> > was using to test this, but I am fairly sure this used to work for me.
> >
> > ...Art
> >
> > On Nov 6, 2007 3:17 PM, Scott Silva <ssilva at sgvwater.com> wrote:
> >> on 11/6/2007 12:01 PM Art Baldini spake the following:
> >>
> >>> Updating the command syntax below.
> >>>
> >>> On Nov 6, 2007 3:00 PM, Art Baldini <rootajb at gmail.com> wrote:
> >>>> I have been trying to delete an md.  I have recently updated to
> >>>> version 1.12 of mdadm.
> >>>> I used to be able to do mdadm /dev/md12 --stop.  It does not seem to be
> >>>> stopping, but I do not get any error and the $?/return code is 0.
> >>>>
> >>>> The --verbose option for mdadm does nothing for --stop.  How do I
> >>>> determine why this is not successful?
> >>>>
> >>>>
> >>>> Thanks...Art
> >>>>
> >> According to the man page;
> >> If a device is given before any options, or if the first option is --add,
> >> --fail, or --remove, then the MANAGE mode is assume. Anything other than these
> >> will cause the Misc mode to be assumed.
> >> So try mdadm --stop /dev/md12  with the device last.
> >>
> >> --
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> >> you notice quickly if they don't!!!!
> >>
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> >>
>
>
> </quote>
>
> --
>
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