[DRBD-user] Increasing a DRBD array

Gerald Brandt gbr at majentis.com
Fri Oct 21 23:39:17 CEST 2011

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


Hi,

I just saw that (google is my friend).  Can I change that on a running drbd system?

ie:

original:

        on iscsi-filer-1 {
        device  /dev/drbd1;
        disk    /dev/md0;
        address 192.168.95.1:7789;
        meta-disk /dev/sda6[1];
        }

        on iscsi-filer-2 {
        device  /dev/drbd1;
        disk    /dev/md0;
        address 192.168.95.2:7789;
        meta-disk /dev/sda6[1];
        }

new:

        on iscsi-filer-1 {
        device  /dev/drbd1;
        disk    /dev/md0;
        address 192.168.95.1:7789;
        flexible-meta-disk /dev/sda6[1];
        }

        on iscsi-filer-2 {
        device  /dev/drbd1;
        disk    /dev/md0;
        address 192.168.95.2:7789;
        flexible-meta-disk /dev/sda6[1];
        }

Then reboot primary, followed by reboot secondary (after sync), and all will be well?

Sorry if these seem to be noob questions.  I just want to be 100% sure, as the file servers have live data on them.

Gerald


----- Original Message -----
> From: "Andreas Kurz" <andreas at hastexo.com>
> To: drbd-user at lists.linbit.com
> Sent: Friday, October 21, 2011 4:26:13 PM
> Subject: Re: [DRBD-user] Increasing a DRBD array
> 
> On 10/21/2011 10:48 PM, Gerald Brandt wrote:
> > Hi,
> > 
> > DRBD is running directly on md0.  /dev/drbd1 is then exported via
> > iSCSI.
> > 
> > The logs show:
> > Oct 21 15:34:53 iscsi-filer-1 kernel: [    7.332010] drbd:
> > initialized.
> > Version: 8.3.7 (api:88/proto:86-91)
> > Oct 21 15:34:53 iscsi-filer-1 kernel: [    7.332012] drbd:
> > GIT-hash:
> > ea9e28dbff98e331a62bcbcc63a6135808fe2917 build by root at filer-1,
> > 2011-03-05 08:29:38
> > Oct 21 15:34:53 iscsi-filer-1 kernel: [    7.332014] drbd:
> > registered as
> > block device major 147
> > Oct 21 15:34:53 iscsi-filer-1 kernel: [    7.332015] drbd:
> > minor_table @
> > 0xffff88021dbaf300
> > Oct 21 15:34:53 iscsi-filer-1 kernel: [    7.334144] block drbd1:
> > Starting worker thread (from cqueue [1489])
> > Oct 21 15:34:53 iscsi-filer-1 kernel: [    7.334177] block drbd1:
> > ==>
> > truncating very big lower level device to currently maximum
> > possible
> > 8587575296 sectors <==
> > Oct 21 15:34:53 iscsi-filer-1 kernel: [    7.334179] block drbd1:
> > ==>>
> > using internal or flexible meta data may help <<==
> > Oct 21 15:34:53 iscsi-filer-1 kernel: [    7.334188] block drbd1:
> > disk(
> > Diskless -> Attaching )
> > Oct 21 15:34:53 iscsi-filer-1 kernel: [    7.353306] Loading iSCSI
> > transport class v2.0-870.
> > Oct 21 15:34:53 iscsi-filer-1 kernel: [    7.360582] skge eth0:
> > disabling interface
> > Oct 21 15:34:53 iscsi-filer-1 iscsid: iSCSI logger with pid=1515
> > started!
> > Oct 21 15:34:53 iscsi-filer-1 kernel: [    7.381956] iscsi:
> > registered
> > transport (iser)
> > Oct 21 15:34:53 iscsi-filer-1 init: ssh main process (1162)
> > terminated
> > with status 255
> > Oct 21 15:34:53 iscsi-filer-1 postfix/master[1411]: reload --
> > version
> > 2.7.0, configuration /etc/postfix
> > Oct 21 15:34:54 iscsi-filer-1 kernel: [    7.584678] block drbd1:
> > Found
> > 57 transactions (3507 active extents) in activity log.
> > Oct 21 15:34:54 iscsi-filer-1 kernel: [    7.584684] block drbd1:
> > Method
> > to ensure write ordering: barrier
> > Oct 21 15:34:54 iscsi-filer-1 kernel: [    7.584691] block drbd1:
> > Backing device's merge_bvec_fn() = ffffffffa00c0100
> > Oct 21 15:34:54 iscsi-filer-1 kernel: [    7.584694] block drbd1:
> > max_segment_size ( = BIO size ) = 4096
> > Oct 21 15:34:54 iscsi-filer-1 kernel: [    7.584698] block drbd1:
> > Adjusting my ra_pages to backing device's (32 -> 96)
> > Oct 21 15:34:54 iscsi-filer-1 kernel: [    7.584704] block drbd1:
> > drbd_bm_resize called with capacity == 8587575296
> > Oct 21 15:34:54 iscsi-filer-1 kernel: [    7.603470] block drbd1:
> > resync
> > bitmap: bits=1073446912 words=16772608
> > Oct 21 15:34:54 iscsi-filer-1 kernel: [    7.603474] block drbd1:
> > size =
> > 4095 GB (4293787648 KB)
> > 
> > The lines in yellow bug me.  I don't recall see them before.
> > 
> > I had a 4 disk RAID-6 md0 (4x2TB = 4 TB RAID-6).  I added a single
> > drive
> > (5x2TB = 6 TB array).
> 
> Not using "meta-disk internal" or "flexible-meta-disk" limits the
> device
> size to 4TB (=128MB meta data size) ... change your metadata config
> ...
> as the logs suggest ... if you want to use all 6TB
> 
> Regards,
> Andreas
> 
> --
> Need help with DRBD?
> http://www.hastexo.com/now
> 
> > 
> > Any ideas?
> > 
> > Gerald
> > 
> > 
> > ------------------------------------------------------------------------
> > 
> >     From: "Andreas Kurz" <andreas at hastexo.com>
> >      To: drbd-user at lists.linbit.com
> >      Sent: Friday, October 21, 2011 2:55:06 PM
> >      Subject: Re: [DRBD-user] Increasing a DRBD array
> >      
> >      On 10/21/2011 09:30 PM, Gerald Brandt wrote:
> >      > Hi,
> >      >
> >      > I've successfully resize the lower level RAID-6 array, and
> >      > grown
> >      > it.  I'm now attempting to resize drbd, and nothing seems to
> >      > happen.
> >      >
> >      > /dev/md0 is definitely bigger.
> >      >
> >      > What should I see during a drbd resize?
> >      
> >      You should see a DRBD resync of the newly added space.
> >      
> >      What is the lower level device of your DRBD resource? The
> >      whole md0,
> >      a
> >      partition on md0, a lv on a vg on a pv on md0?
> >      
> >      ... so if the lower level device has been resized on both
> >      nodes, DRBD
> >      should definitely grow on a "drbdadm resize".
> >      
> >      Did I mention that on starting DRBD it is resized
> >      automatically if a
> >      bigger lower level device is detected? ... have a look at the
> >      kernel
> >      logs...
> >      
> >      Regards,
> >      Andreas
> >      
> >      --
> >      Need help with DRBD?
> >      http://www.hastexo.com/now
> >      
> >      >
> >      > Gerald
> >      >
> >      >
> >      > ----- Original Message -----
> >      >> From: "Gerald Brandt" <gbr at majentis.com>
> >      >> To: drbd-user at lists.linbit.com
> >      >> Sent: Tuesday, October 18, 2011 7:08:55 AM
> >      >> Subject: Re: [DRBD-user] Increasing a DRBD array
> >      >>
> >      >> Hi,
> >      >>
> >      >> Okay, this is my list of what to do, and in what order:
> >      >>
> >      >> 1. remove the primary from DRBD
> >      >> 2. add the physical disk to the primary
> >      >> 3. add the primary back to DRBD and allow resync.
> >      >> 4. remove the secondary from DRBD
> >      >> 5. add the physical disk to the secondary
> >      >> 6. add the secondary back to DRBD and allow resync.
> >      >> 7. fdisk and add the disk to the RAID array on primary and
> >      >> secondary
> >      >> 8. grow the RAID array on the primary and secondary (while
> >      >> mounted
> >      >> or
> >      >> not mounted?)
> >      >> 9. drbdadm resize on the primary (can this be done while
> >      >> drbd is
> >      >> in
> >      >> use?)
> >      >> 10. expand the file system on the primary only (via Citrix
> >      >> XenServer
> >      >> (iSCSI))
> >      >>
> >      >> That sounds about right.  As long as I don't lose data.
> >      >> (yeah,
> >      >> backups.  That's left up to my client, but becomes my
> >      >> problem if
> >      >> they failed.)
> >      >>
> >      >> Gerald
> >      >>
> >      >>
> >      >>
> >      >> ----- Original Message -----
> >      >>> From: "Florian Haas" <florian at hastexo.com>
> >      >>> To: drbd-user at lists.linbit.com
> >      >>> Sent: Tuesday, October 18, 2011 3:53:11 AM
> >      >>> Subject: Re: [DRBD-user] Increasing a DRBD array
> >      >>>
> >      >>> On 2011-10-17 22:19, Matt Graham wrote:
> >      >>>>>> Your DRBD uses the MD RAID as its backing device,
> >      >>>>>> doesn't it?
> >      >>>>>> That means you'll have add the drive and resize your
> >      >>>>>> RAID
> >      >>>>>> first,
> >      >>>>>> then
> >      >>>>>> you can resize your DRBD, and then expand the file
> >      >>>>>> system.
> >      >>>>> Definitely built on top of the RAID.  I'm a bit confused
> >      >>>>> by
> >      >>>>> your
> >      >>>>> answer though.  Step 8 grows the RAID array, and I don't
> >      >>>>> have a
> >      >>>>> step
> >      >>>>> to grow DRBD.  Does that mean I'm missing something?
> >      >>>>
> >      >>>> 8. mdadm --grow /dev/md0 (other mdadm options)
> >      >>>>    Do that on both machines.
> >      >>>> 8.1 (on secondary) drbdsetup /dev/drbd0 resize
> >      >>>> 8.2 (on primary) drbdsetup /dev/drbd0 resize
> >      >>>
> >      >>> There's a "resize" subcommand for drbdadm too; no need to
> >      >>> use
> >      >>> drbdsetup.
> >      >>> And it needs to be done on one node only. Just do "drbdadm
> >      >>> resize
> >      >>> <resourcename>" on the primary while the two nodes are
> >      >>> connected,
> >      >>> and
> >      >>> you're good to go.
> >      >>>
> >      >>>>    The softRAID is below the DRBD device.  Once the
> >      >>>>    softRAID is
> >      >>>>    larger, the DRBD device needs to be informed of this
> >      >>>>    fact.
> >      >>>>    When making arrays/devices larger, you go bottom-up;
> >      >>>>    you make
> >      >>>>    the hardware changes first, then softRAID changes,
> >      >>>>    then DRBD
> >      >>>>    changes, then filesystem changes.
> >      >>>> 9. (on primary) resize2fs /dev/drbd0
> >      >>>
> >      >>> If it's ext3 and if it supports on-line resizing, of
> >      >>> course. But
> >      >>> that
> >      >>> should be obvious.
> >      >>>
> >      >>> Cheers,
> >      >>> Florian
> >      >>>
> >      >>> --
> >      >>> Need help with DRBD?
> >      >>> http://www.hastexo.com/knowledge/drbd
> >      >>> _______________________________________________
> >      >>> drbd-user mailing list
> >      >>> drbd-user at lists.linbit.com
> >      >>> http://lists.linbit.com/mailman/listinfo/drbd-user
> >      >>>
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> >      
> >      
> >      
> >      
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> >      
> > 
> > 
> > 
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> 
> 
> 
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