Re: About scrub and deep-scrub

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Yes, I understand. Many thank Eugen

Vào Th 2, 7 thg 10, 2024 vào lúc 16:29 Eugen Block <eblock@xxxxxx> đã
viết:

> Well, if you have more PGs, the deep-scrubs per PG finish faster, but
> you have more PGs to scrub. But that way you can stretch the
> deep-scrub interval. As I said, I can not recommend to increase them
> in general. Overloading OSDs with too many PGs can have a negative
> effect as well. If you can, I'd probably rather add more (smaller)
> OSDs to spread the PGs.
>
> Zitat von Phong Tran Thanh <tranphong079@xxxxxxxxx>:
>
> > Hi Eugen
> >
> > Adding PG to the cluster only helps to reduce PG size and reduce scrub
> time
> > is right? >150 PG and <200 in osd i think it's good number
> >
> > My cluster I/O 2-3GB/s real time in 24h IOPS 2K. If choosing to increase
> PG
> > is it a good choice?
> >
> > Vào Th 2, 7 thg 10, 2024 vào lúc 15:49 Eugen Block <eblock@xxxxxx> đã
> > viết:
> >
> >> So your PGs for pool 52 have a size of around 320 GB, that is quite a
> >> lot and not surprising that deep-scrubs take a long time. At the same
> >> time, your PGs per OSD are already > 150. We had a similar situation
> >> on a customer cluster this year as well, also with 12 TB drives. We
> >> decided to increase the pg_num anyway to reduce the pg sizes. They
> >> currently have around 380 PGs per large OSD (they have lots of smaller
> >> OSDs as well) which still works fine. But they're using it as an
> >> archive, so the IO is not very high. If you would decide to split PGs,
> >> keep in mind to increase mon_max_pg_per_osd and
> >> osd_max_pg_per_osd_hard_ratio as well. I can't explicitly recommend to
> >> double your PGs per OSD as I'm not familiar with your cluster, the
> >> load etc. It's just something to think about.
> >> Doubling the PG count would reduce the PG size to around 160 GB, which
> >> is still a lot, but I probably wouldn't go further than that.
> >> The OSD utilization is only around 40%, in this case a cluster with
> >> more (smaller) OSDs would probably have made more sense.
> >>
> >> Zitat von Phong Tran Thanh <tranphong079@xxxxxxxxx>:
> >>
> >> > Hi Eugen
> >> >
> >> > Can you see and give me some advice, number of PG and PG size..
> >> >
> >> > ID   CLASS  WEIGHT    REWEIGHT  SIZE     RAW USE  DATA     OMAP
>  META
> >> >   AVAIL    %USE   VAR   PGS  STATUS
> >> >   2    hdd  10.98349   1.00000   11 TiB  4.5 TiB  4.2 TiB  5.0 MiB
>  12
> >> GiB
> >> >  6.5 TiB  40.77  1.00  182      up
> >> >  17    hdd  10.98349   1.00000   11 TiB  4.8 TiB  4.6 TiB   22 MiB
>  14
> >> GiB
> >> >  6.1 TiB  44.16  1.08  196      up
> >> >  32    hdd  10.98349   1.00000   11 TiB  4.3 TiB  4.0 TiB   37 MiB
>  12
> >> GiB
> >> >  6.7 TiB  38.80  0.95  173      up
> >> >  47    hdd  10.98349   1.00000   11 TiB  4.2 TiB  3.9 TiB  655 KiB
>  11
> >> GiB
> >> >  6.8 TiB  38.16  0.93  184      up
> >> >  60    hdd  10.98349   1.00000   11 TiB  4.3 TiB  4.0 TiB   19 MiB
>  12
> >> GiB
> >> >  6.6 TiB  39.47  0.96  176      up
> >> >  74    hdd  10.98349   1.00000   11 TiB  4.2 TiB  3.9 TiB   28 MiB
>  12
> >> GiB
> >> >  6.8 TiB  38.10  0.93  187      up
> >> >  83    hdd  10.98349   1.00000   11 TiB  4.8 TiB  4.5 TiB  1.9 MiB
>  14
> >> GiB
> >> >  6.2 TiB  43.47  1.06  180      up
> >> >  96    hdd  10.98349   1.00000   11 TiB  4.3 TiB  4.0 TiB   38 MiB
>  12
> >> GiB
> >> >  6.7 TiB  38.80  0.95  181      up
> >> > 110    hdd  10.98349   1.00000   11 TiB  4.5 TiB  4.2 TiB  4.3 MiB
>  13
> >> GiB
> >> >  6.5 TiB  40.79  1.00  174      up
> >> > 123    hdd  10.98349   1.00000   11 TiB  4.2 TiB  3.9 TiB  1.9 MiB
>  13
> >> GiB
> >> >  6.8 TiB  38.11  0.93  173      up
> >> > 136    hdd  10.98349   1.00000   11 TiB  4.3 TiB  4.0 TiB   43 MiB
>  12
> >> GiB
> >> >  6.6 TiB  39.46  0.96  179      up
> >> > .....
> >> >
> >> > PG      OBJECTS  DEGRADED  MISPLACED  UNFOUND  BYTES
>  OMAP_BYTES*
> >> >  OMAP_KEYS*  LOG   LOG_DUPS  STATE                        SINCE
> >> > 52.0      80121         0          0        0  323105248            0
> >> >         0  1747      3000                 active+clean    94m
> >> > 52.1      79751         0          0        0  321711556766
>   0
> >> >         0  1727      3000                 active+clean    21h
> >> > 52.2      80243         0          0        0  323711878626
>   0
> >> >         0  1618      3000                 active+clean    30h
> >> > 52.3      79892         0          0        0  322166010020
>   0
> >> >         0  1627      3000                 active+clean     9h
> >> > 52.4      80267         0          0        0  323708219486
>   0
> >> >         0  1658      3000                 active+clean     5h
> >> > 52.5      79996         0          0        0  322331504454
>   0
> >> >         0  1722      3000                 active+clean    18h
> >> > 52.6      80190         0          0        0  323460394402
>   0
> >> >         0  1759      3000                 active+clean    15h
> >> > 52.7      79998         0          0        0  322769143546
>   0
> >> >         0  1720      3000                 active+clean    26h
> >> > 52.8      80292         0          0        0  323932173152
>   0
> >> >         0  1691      3000                 active+clean    21h
> >> > 52.9      79808         0          0        0  321910742702
>   0
> >> >         0  1675      3000                 active+clean     7h
> >> > 52.a      79751         0          0        0  321578061334
>   0
> >> >         0  1822      3000                 active+clean    26h
> >> > 52.b      80287         0          0        0  323905164642
>   0
> >> >         0  1793      3000                 active+clean     6h
> >> > ....
> >> > Thanks Eugen
> >> >
> >> > Vào Th 2, 7 thg 10, 2024 vào lúc 14:45 Eugen Block <eblock@xxxxxx>
> đã
> >> > viết:
> >> >
> >> >> Hi,
> >> >>
> >> >> disabling scrubbing in general is bad idea, because you won't notice
> >> >> any data corruption except when it might be too late.
> >> >> But you can fine tune scrubbing, for example increase the interval to
> >> >> allow fewer scrubs to finish in a longer interval. Or if the client
> >> >> load is mainly during business hours, adjust osd_scrub_begin_hour and
> >> >> osd_scrub_end_hour to your needs.
> >> >> And it also depends on the size of your PGs. The larger the PGs are,
> >> >> the longer a deep-scrub would take. So splitting PGs can have a quite
> >> >> positive effect in general. Inspect 'ceph osd df' output as well as
> >> >> 'ceph pg ls' (BYTES column), you can also share it here if you need
> >> >> assistance interpreting those values.
> >> >>
> >> >> Regards,
> >> >> Eugen
> >> >>
> >> >> Zitat von Phong Tran Thanh <tranphong079@xxxxxxxxx>:
> >> >>
> >> >> > Hi ceph users!
> >> >> >
> >> >> > How about the disable scrub and deep-scrub, i want to disable it
> >> because
> >> >> of
> >> >> > its effect on many I/O of my cluster.
> >> >> > If I disable scrub how will it affect my cluster?
> >> >> > If enabled, scrubbing is not complete and takes a long time.
> >> >> >
> >> >> >
> >> >> > Thank
> >> >> > Skype: tranphong079
> >> >> > _______________________________________________
> >> >> > ceph-users mailing list -- ceph-users@xxxxxxx
> >> >> > To unsubscribe send an email to ceph-users-leave@xxxxxxx
> >> >>
> >> >>
> >> >> _______________________________________________
> >> >> ceph-users mailing list -- ceph-users@xxxxxxx
> >> >> To unsubscribe send an email to ceph-users-leave@xxxxxxx
> >> >>
> >> >
> >> >
> >> > --
> >> > Trân trọng,
> >> >
> >>
> ----------------------------------------------------------------------------
> >> >
> >> > *Tran Thanh Phong*
> >> >
> >> > Email: tranphong079@xxxxxxxxx
> >> > Skype: tranphong079
> >>
> >>
> >>
> >>
> >
> > --
> > Trân trọng,
> >
> ----------------------------------------------------------------------------
> >
> > *Tran Thanh Phong*
> >
> > Email: tranphong079@xxxxxxxxx
> > Skype: tranphong079
>
>
>
>

-- 
Trân trọng,
----------------------------------------------------------------------------

*Tran Thanh Phong*

Email: tranphong079@xxxxxxxxx
Skype: tranphong079
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