[lustre-discuss] FLR mirroring on 2.12.1-1

[John Doe]

It turns out that the read eventually finished and was 1/10th of the
performance that I was expecting.

As ost idx 1 is unavailable, the client read has to timeout on ost idx 1
and then will read from ost idx 7. This happens for each 1MB block, as I am
using that as the block size.

Is there a tunable to avoid this issue?

lfs check osts also takes about 30 seconds as it times out on the
unavailable OST.

Due to this issue, I am virtually unable to use the mirroring feature.

I

On Sun, May 19, 2019 at 4:27 PM John Doe <ace629426 at gmail.com> wrote:

> After mirroring a file , when one mirror is down, any reads from a client
> just hangs. Both server and client are running latest 2.12.1-1. Client
> waits for ost idx 1 to come back online.  I am only unmounting ost idx1 not
> ost idx 7.
>
> Has anyone tried this feature?
>
> Thanks,
> John.
>
> lfs getstripe mirror10
> mirror10
>   lcm_layout_gen:    5
>   lcm_mirror_count:  2
>   lcm_entry_count:   2
>     lcme_id:             65537
>     lcme_mirror_id:      1
>     lcme_flags:          init
>     lcme_extent.e_start: 0
>     lcme_extent.e_end:   EOF
>       lmm_stripe_count:  1
>       lmm_stripe_size:   1048576
>       lmm_pattern:       raid0
>       lmm_layout_gen:    0
>       lmm_stripe_offset: 1
>       lmm_pool:          01
>       lmm_objects:
>       - 0: { l_ost_idx: 1, l_fid: [0x100010000:0x280a8:0x0] }
>
>     lcme_id:             131074
>     lcme_mirror_id:      2
>     lcme_flags:          init
>     lcme_extent.e_start: 0
>     lcme_extent.e_end:   EOF
>       lmm_stripe_count:  1
>       lmm_stripe_size:   1048576
>       lmm_pattern:       raid0
>       lmm_layout_gen:    0
>       lmm_stripe_offset: 7
>       lmm_pool:          02
>       lmm_objects:
>       - 0: { l_ost_idx: 7, l_fid: [0x100070000:0x28066:0x0] }
>
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