Re: Resync issue in RAID1

[V <viswesh.vichu@gmail.com>]

Hi Neil,

Thanks for the response. But during this phase, why is the scsi driver
complaining about bad block number ?

Oct 18 03:52:56  kernel: [  52.869378] sd 0:0:0:0: [sda] Bad block
number requested
Oct 18 03:52:56  kernel: [  52.869414] sd 0:0:0:0: [sda] Bad block
number requested
Oct 18 03:52:56  kernel: [  52.869436] sd 0:0:0:0: [sda] Bad block
number requested
Oct 18 03:52:56  kernel: [  52.869465] sd 0:0:0:0: [sda] Bad block
number requested
Oct 18 03:52:56  kernel: [  52.869503] sd 0:0:1:0: [sdb] Bad block
number requested

Thanks,
V

On Thu, Oct 27, 2016 at 9:01 PM, NeilBrown <neilb@suse.com> wrote:
> On Sat, Oct 22 2016, V wrote:
>
>> Hi,
>>
>> I am facing an issue during RAID1 resync. I have an ubuntu
>> 4.4.0-31-generic running with raid1 configured with 2 disks as active
>> and 2 as spares. On the first powercycle, after installing RAID, i see
>> the following messages in kern.log
>>
>>
>> My disks are configured with 4K sector size (both logical and
>> physical) (sda and sdb are active disks for this raid)
>>
>>
>> ===========
>> Oct 18 03:52:56  kernel: [   52.869113] md: using 128k window, over a
>> total of 51167104k.
>> Oct 18 03:52:56  kernel: [   52.869114] md: resuming resync of md2 from checkpoint.
>
> This line (above) combined with ...
>
>> Oct 18 03:52:56  kernel: [   52.869536] md/raid1:md2: sda: unrecoverable I/O read error for block 3
>
> this line suggests that when you shut down, md had already started a
> resync, and it had checkpointed at block '3'.
>
> The subsequent error are:
>
>> Oct 18 03:52:56  kernel: [   52.869692] md/raid1:md2: sda: unrecoverable I/O read error for block 131
>> Oct 18 03:52:56  kernel: [   52.869837] md/raid1:md2: sda: unrecoverable I/O read error for block 259
>> Oct 18 03:52:56  kernel: [   52.870022] md/raid1:md2: sda: unrecoverable I/O read error for block 387
>
> which are every 128 blocks (aka sectors) from '3'.
> I know what caused that.  The patch below will stop it happening again.
>
> You might be able get your array working again by stopping it
> and assembling with --update=resync.
> That will reset the checkpoint to 0.
>
> NeilBrown
>
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index 2cf0e1c00b9a..aa2ca23463f4 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -8099,7 +8099,8 @@ void md_do_sync(struct md_thread *thread)
>             mddev->curr_resync > 2) {
>                 if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
>                         if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
> -                               if (mddev->curr_resync >= mddev->recovery_cp) {
> +                               if (mddev->curr_resync >= mddev->recovery_cp &&
> +                                   mddev->curr_resync > 3) {
>                                         printk(KERN_INFO
>                                                "md: checkpointing %s of %s.\n",
>                                                desc, mdname(mddev));