[DRBD-user] Secondary node io-error

Florian Haas florian at hastexo.com
Wed Oct 10 10:16:37 CEST 2012

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


On Wed, Oct 10, 2012 at 5:42 AM, Velayutham, Prakash
<Prakash.Velayutham at cchmc.org> wrote:
> Just wanted to add this. I repeated my test again and get the exact same results again. Here is /proc/drbd of the primary (bmimysqlt3) and secondary (bmimysqlt4) before the secondary's disk is cut off (disabling the fiber switch port that the secondary is connected to)
>
> [root at bmimysqlt3 ~]# cat /proc/drbd
> version: 8.4.2 (api:1/proto:86-101)
> GIT-hash: 7ad5f850d711223713d6dcadc3dd48860321070c build by root at bmimysqlt3.chmcres.cchmc.org, 2012-10-02 00:02:32
>  0: cs:Connected ro:Primary/Secondary ds:UpToDate/UpToDate C r-----
>     ns:184 nr:0 dw:160 dr:14317 al:6 bm:6 lo:0 pe:0 ua:0 ap:0 ep:1 wo:f oos:0
>
> [root at bmimysqlt4 ~]# cat /proc/drbd
> version: 8.4.2 (api:1/proto:86-101)
> GIT-hash: 7ad5f850d711223713d6dcadc3dd48860321070c build by root at bmimysqlt3.chmcres.cchmc.org, 2012-10-02 00:02:32
>  0: cs:Connected ro:Secondary/Primary ds:UpToDate/UpToDate C r-----
>     ns:0 nr:184 dw:184 dr:0 al:0 bm:6 lo:0 pe:0 ua:0 ap:0 ep:1 wo:f oos:0
>
> Here is /proc/drbd of primary and secondary about 5 minutes after the disk is cut off.
>
> [root at bmimysqlt3 ~]# cat /proc/drbd
> version: 8.4.2 (api:1/proto:86-101)
> GIT-hash: 7ad5f850d711223713d6dcadc3dd48860321070c build by root at bmimysqlt3.chmcres.cchmc.org, 2012-10-02 00:02:32
>  0: cs:Connected ro:Primary/Secondary ds:UpToDate/UpToDate C r-----
>     ns:184 nr:0 dw:160 dr:14317 al:6 bm:6 lo:0 pe:0 ua:0 ap:0 ep:1 wo:f oos:0
>
> [root at bmimysqlt4 ~]# cat /proc/drbd
> version: 8.4.2 (api:1/proto:86-101)
> GIT-hash: 7ad5f850d711223713d6dcadc3dd48860321070c build by root at bmimysqlt3.chmcres.cchmc.org, 2012-10-02 00:02:32
>  0: cs:Connected ro:Secondary/Primary ds:UpToDate/UpToDate C r-----
>     ns:0 nr:184 dw:184 dr:0 al:0 bm:6 lo:0 pe:0 ua:0 ap:0 ep:1 wo:f oos:0
>
> As you can see, there is absolutely nothing there to suggest that the secondary even noticed the io-error.

At the risk of asking a silly question, how much I/O (on the Primary)
went on after you cut the fiber connection on your Secondary? Was
there any?

In terms of which logs would be useful, a dump of your kernel logs
(kern.log or dmesg), grepped for "drbd0" and pastebinned, would
probably help.

Cheers,
Florian

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