DRBD

Постановка задачи

Требуется создать отказоустойчивый кластер с общим хранилищем данных. Область применения - кластера www-серверов (с распределением запросов round-robin-dns или аппаратными load-balancer).

Установка (gentoo)

Конфиг ядра

Для DRBD требуется connector.

Linux Kernel Configuration: Поддержка DRBD

Device Drivers ---> <*> Connector - unified userspace <-> kernelspace linker --->

Установка модулей ядра и ПО для работы с DRBD

ПО для работы с DRBD и модули помечены как нестабильные. Добавить в /etc/portage/package.unmask:

sys-cluster/drbd
sys-cluster/drbd-kernel

и, соответвенно, для архитектуры которая используется в /etc/portage/package.keywords

sys-cluster/drbd ~amd64
sys-cluster/drbd-kernel ~amd64

Простой конфиг

global {
  usage-count no;
}

common {
    protocol C;
}

resource r0 {
    on sirmax {
        device    /dev/drbd1;
        disk      /dev/sda7;
        address   10.1.1.31:7789;
        meta-disk internal;
    }


    on nightmare {
        device    /dev/drbd1;
        disk      /dev/sda7;
        address   10.1.1.32:7789;
        meta-disk internal;
    }
}

1. modprobe drbd
2. drbdadm create-md drbd0

drbdadm create-md r0 md_offset 41883086848 al_offset 41883054080 bm_offset 41881772032

Found some data

==> This might destroy existing data! <==

Do you want to proceed? [need to type 'yes' to confirm] yes

Writing meta data... initializing activity log NOT initialized bitmap New drbd meta data block successfully created.

1. drbdadm attach drbd0
2. drbdadm connect drbd0

dmesg
[86352.936619] drbd1: disk( Diskless -> Attaching )
[86352.936625] drbd1: Starting worker thread (from cqueue [20959])
[86352.937639] drbd1: No usable activity log found.
[86352.937644] drbd1: max_segment_size ( = BIO size ) = 32768
[86352.937648] drbd1: drbd_bm_resize called with capacity == 81800336
[86352.938477] drbd1: resync bitmap: bits=10225042 words=159767
[86352.938482] drbd1: size = 39 GB (40900168 KB)
[86352.938494] drbd1: Writing the whole bitmap, size changed
[86352.977094] drbd1: 39 GB (10225042 bits) marked out-of-sync by on disk bit-map.
[86353.006166] drbd1: recounting of set bits took additional 1 jiffies
[86353.006171] drbd1: 39 GB (10225042 bits) marked out-of-sync by on disk bit-map.
[86353.006178] drbd1: disk( Attaching -> Inconsistent )
[86381.994378] drbd1: conn( StandAlone -> Unconnected )
[86381.994398] drbd1: Starting receiver thread (from drbd1_worker [21012])
[86381.994459] drbd1: receiver (re)started
[86381.994469] drbd1: conn( Unconnected -> WFConnection )

drbdadm -- --overwrite-data-of-peer primary r0

cat /proc/drbd
version: 8.0.16 (api:86/proto:86)
GIT-hash: d30881451c988619e243d6294a899139eed1183d build by root@nightmare, 2009-08-31 14:34:25

 1: cs:SyncSource st:Primary/Secondary ds:UpToDate/Inconsistent C r---
    ns:5408 nr:0 dw:0 dr:5408 al:0 bm:0 lo:0 pe:0 ua:0 ap:0
        [>....................] sync'ed:  0.1% (39936/39940)M
        finish: 28:23:56 speed: 360 (336) K/sec
        resync: used:0/61 hits:337 misses:1 starving:0 dirty:0 changed:1
        act_log: used:0/257 hits:0 misses:0 starving:0 dirty:0 changed:0

Ссылки

http://www.netup.ru/articles.php?n=13
http://habrahabr.ru/blogs/hi/50143/
http://wiki.samba.org/index.php/6.0._DRBD
http://xgu.ru/wiki/DRBD
http://b2d.kiev.ua/blog/?p=7
http://sources.redhat.com/cluster/doc/usage.txt
http://blog.sozinov.eu/2008/10/gfs-global-file-system.html