[DRBD-user] Slow resync

A.Rubio aurusa at etsii.upv.es
Tue Jan 5 11:20:19 CET 2016

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


Test this options

net {
     max-buffers 8000;
     max-epoch-size 8000;
     max-buffers 16000;
     max-epoch-size 16000;
     unplug-watermark 16;
     unplug-watermark 16000;
}


disk {
     no-disk-barrier;
     no-disk-flushes;
}

syncer {
     al-extents 3389;
}




El 04/01/16 a las 17:48, Ricardo Branco escribió:
> I have an odd situation with resync.
>
> Resync seems to always be limited to max 40MB/s, if I am doing both of 
> my resources at the same time then both are at 40MB/s (total 80M), but 
> never goes above this.
> If I copy a 20G file which is on drbd then the sync speed to the other 
> server reaches 800GB/s, doing a dd gives similar results around 1GB/s.
> Does not matter what param I tweek i can not get the sync speed to be 
> above 40MB/s.
> To test that cachecade is not getting in the way I have disabled it 
> for tests but nothing changed.
>
> This server has been running 8.4.3 up to recently, now 8.4.6.
> Before the upgrade I am sure when I did a sync I saw much higher 
> resync rates.
>
> The server setup is:
> 16x 3TB SAS 7.2k RAID 6 on LSI Megaraid 9271-4i (FBWC + CacheCade)
> 10G Ethernet direct link between servers
>
>
> Config:
> resource d0 {
>     options {
>         cpu-mask                ""; # default
>         on-no-data-accessible   io-error; # default
>     }
>     net {
>         protocol                C; # default
>         timeout                 60; # 1/10 seconds, default
>         max-epoch-size          2048; # default
>         max-buffers             2048; # default
>         unplug-watermark        128; # default
>         connect-int             10; # seconds, default
>         ping-int                10; # seconds, default
>         sndbuf-size             0; # bytes, default
>         rcvbuf-size             0; # bytes, default
>         ko-count                7; # default
>         allow-two-primaries     no; # default
>         cram-hmac-alg           ""; # default
>         shared-secret           ""; # default
>         after-sb-0pri           disconnect; # default
>         after-sb-1pri           disconnect; # default
>         after-sb-2pri           disconnect; # default
>         always-asbp             no; # default
>         rr-conflict             disconnect; # default
>         ping-timeout            5; # 1/10 seconds, default
>         data-integrity-alg      ""; # default
>         tcp-cork                yes; # default
>         on-congestion           block; # default
>         congestion-fill         0s; # bytes, default
>         congestion-extents      1237; # default
>         csums-alg               ""; # default
>         csums-after-crash-only  no; # default
>         verify-alg              "crc32c";
>         use-rle                 yes; # default
>         socket-check-timeout    0; # default
>     }
>     _remote_host {
>         address                 ipv4 192.168.10.1:7789;
>     }
>     _this_host {
>         address                 ipv4 192.168.10.2:7789;
>         volume 0 {
>             device                      minor 1;
>             disk                        "/dev/vg_raid1/drbd0";
>             meta-disk                   internal;
>             disk {
>                 size                    0s; # bytes, default
>                 max-bio-bvecs           0; # default
>                 on-io-error             detach; # default
>                 fencing                 resource-only;
>                 disk-barrier            no; # default
>                 disk-flushes            no;
>                 disk-drain              yes; # default
>                 md-flushes              yes; # default
>                 resync-rate             512000k; # bytes/second
>                 resync-after            -1; # default
>                 al-extents              1237; # default
>                 al-updates              yes; # default
>                 c-plan-ahead            0; # 1/10 seconds
>                 c-delay-target          10; # 1/10 seconds, default
>                 c-fill-target           100s; # bytes, default
>                 c-max-rate              102400k; # bytes/second, default
>                 c-min-rate              250k; # bytes/second, default
>                 disk-timeout            0; # 1/10 seconds, default
>                 read-balancing          prefer-local; # default
>             }
>         }
>     }
> }
>
>  0: cs:SyncTarget ro:Secondary/Primary ds:Inconsistent/UpToDate C r-----
>     ns:0 nr:262361424 dw:325178528 dr:0 al:0 bm:0 lo:0 pe:0 ua:0 ap:0 
> ep:1 wo:d oos:11362364
>         [==>.................] sync'ed: 15.5% (11096/13116)M
>         finish: 0:05:15 speed: 35,944 (31,844) want: 512,000 K/sec
>
>

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