Db20 to NFS1-2 migration plan
From Wikitech
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=== Preparation === | === Preparation === | ||
| − | * Prepare | + | * Check DRAC access |
| + | * Prepare nfs1 for drbd | ||
* Add DNS entries for new internal IPs | * Add DNS entries for new internal IPs | ||
* Set up cross link networking between nfs1/nfs2 | * Set up cross link networking between nfs1/nfs2 | ||
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** replication rate 110M | ** replication rate 110M | ||
* Write final configuration files for nfs1/nfs2 | * Write final configuration files for nfs1/nfs2 | ||
| − | * Install /etc/exports on nfs1/nfs2 | + | * Install <tt>/etc/exports</tt> on nfs1/nfs2 |
* Install NFS kernel server on nfs1/nfs2 | * Install NFS kernel server on nfs1/nfs2 | ||
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disk /dev/mapper/mirror-nfshome; | disk /dev/mapper/mirror-nfshome; | ||
address 10.3.0.1:7789; | address 10.3.0.1:7789; | ||
| − | meta-disk | + | meta-disk internal; |
} | } | ||
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'''On nfs1''': | '''On nfs1''': | ||
| − | * Install new /etc/drbd.conf | + | * Install new <tt>/etc/drbd.conf</tt> |
* Create device meta-data: | * Create device meta-data: | ||
drbdadm create-md nfshome | drbdadm create-md nfshome | ||
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'''On db20''': | '''On db20''': | ||
* Stop NFS kernel server | * Stop NFS kernel server | ||
| − | * Remove NFS service IP 10.0.5.8: | + | * Remove NFS service IP <tt>10.0.5.8</tt>: |
ip addr del 10.0.5.8/32 dev eth0 | ip addr del 10.0.5.8/32 dev eth0 | ||
| − | * Stop userland processes using /home (fuser -m) | + | * Stop userland processes using <tt>/home</tt> (<tt>fuser -m</tt>) |
| − | * Unmount /home | + | * Unmount <tt>/home</tt> |
| − | * Comment /home mount in /etc/fstab | + | * Comment <tt>/home</tt> mount in <tt>/etc/fstab</tt> |
| − | * Check consistency of nfshome replication (cat /proc/drbdadm) | + | * Check consistency of nfshome replication (<tt>cat /proc/drbdadm</tt>) |
* Disable resource: | * Disable resource: | ||
drbdadm down nfshome | drbdadm down nfshome | ||
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'''On nfs2''': | '''On nfs2''': | ||
| − | * Check consistency of nfshome replication (cat /proc/drbdadm) | + | * Check consistency of nfshome replication (<tt>cat /proc/drbdadm</tt>) |
* Disable resource: | * Disable resource: | ||
drbdadm down nfshome | drbdadm down nfshome | ||
* Save the meta-data in a text file: | * Save the meta-data in a text file: | ||
drbdadm dump-md nfshome > /root/db20-nfs2-drbd.metadata | drbdadm dump-md nfshome > /root/db20-nfs2-drbd.metadata | ||
| − | * Install new /etc/drbd.conf | + | * Install new <tt>/etc/drbd.conf</tt> |
* Create device meta-data: | * Create device meta-data: | ||
drbdadm create-md nfshome | drbdadm create-md nfshome | ||
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drbdadm -- --overwrite-data-of-peer primary nfshome | drbdadm -- --overwrite-data-of-peer primary nfshome | ||
* Check replication status (cat /proc/drbd) | * Check replication status (cat /proc/drbd) | ||
| − | * Add /etc/fstab entry: | + | * Add <tt>/etc/fstab</tt> entry: |
/dev/drbd1 /home jfs defaults 0 2 | /dev/drbd1 /home jfs defaults 0 2 | ||
| − | * Mount /home: | + | * Mount <tt>/home</tt>: |
mount /home | mount /home | ||
| − | * Migrate NFS service IP 10.0.5.8 to nfs2: | + | * Migrate NFS service IP <tt>10.0.5.8</tt> to nfs2: |
ip addr add 10.0.5.8/32 dev eth0 | ip addr add 10.0.5.8/32 dev eth0 | ||
| − | * Configure service IP on nfs2 on bootup. Add entry to /etc/networking/interfaces eth0: | + | * Configure service IP on nfs2 on bootup. Add entry to <tt>/etc/networking/interfaces</tt> eth0: |
up ip addr add 10.0.5.8/32 dev $IFACE | up ip addr add 10.0.5.8/32 dev $IFACE | ||
* Start NFS kernel server | * Start NFS kernel server | ||
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=== Rollback === | === Rollback === | ||
| − | If anything goes wrong, the filesystem on /dev/drbd1, or alternatively /dev/sda6 should be in tact and can be mounted. NFS service can then be restored quickly. | + | If anything goes wrong, the filesystem on <tt>/dev/drbd1</tt>, or alternatively <tt>/dev/sda6</tt> should be in tact and can be mounted. NFS service can then be restored quickly. |
| − | [[Category:Migration plans | + | [[Category:Migration plans]] |
Latest revision as of 00:08, 21 February 2012
NFS home DRBD migration plan.
Contents |
[edit] Hosts
- db20 - old server
- nfs1 - fresh host
- nfs2 - host replicating from db20
[edit] Differences
- Move replication from db20->nfs2 to nfs2->nfs1
- Use protocol C, not A
[edit] Plan
[edit] Preparation
- Check DRAC access
- Prepare nfs1 for drbd
- Add DNS entries for new internal IPs
- Set up cross link networking between nfs1/nfs2
- Protocol C, not A
- replication rate 110M
- Write final configuration files for nfs1/nfs2
- Install /etc/exports on nfs1/nfs2
- Install NFS kernel server on nfs1/nfs2
[edit] IP plan
; Cross link between nfs1/nfs2: 10.3.0.0/30 1 1H IN PTR nfs1-xlink0.pmtpa.wmnet. 2 1H IN PTR nfs2-xlink0.pmtpa.wmnet.
nfs1-xlink0 1H IN A 10.3.0.1 nfs2-xlink0 1H IN A 10.3.0.2
[edit] New drbd.conf
# drbd.conf for replication between nfs1 and nfs2
# Written on 2009/11/23 by Mark Bergsma <mark@wikimedia.org>
global {
usage-count no;
}
common {
protocol C;
}
resource nfshome {
on nfs1 {
device /dev/drbd1;
disk /dev/mapper/mirror-nfshome;
address 10.3.0.1:7789;
meta-disk internal;
}
on nfs2 {
device /dev/drbd1;
disk /dev/mapper/mirror-nfshome;
address 10.3.0.2:7789;
meta-disk internal;
}
}
[edit] Migration
On nfs1:
- Install new /etc/drbd.conf
- Create device meta-data:
drbdadm create-md nfshome
- Attach and setup new resource, but do not connect yet:
drbdadm attach nfshome drbdadm syncer nfshome
On db20:
- Stop NFS kernel server
- Remove NFS service IP 10.0.5.8:
ip addr del 10.0.5.8/32 dev eth0
- Stop userland processes using /home (fuser -m)
- Unmount /home
- Comment /home mount in /etc/fstab
- Check consistency of nfshome replication (cat /proc/drbdadm)
- Disable resource:
drbdadm down nfshome
- Save the meta-data in a text file:
drbdadm dump-md nfshome > /root/db20-nfs2-drbd.metadata
nfs2 should now have an exact block level replica of the /home filesystem
On nfs2:
- Check consistency of nfshome replication (cat /proc/drbdadm)
- Disable resource:
drbdadm down nfshome
- Save the meta-data in a text file:
drbdadm dump-md nfshome > /root/db20-nfs2-drbd.metadata
- Install new /etc/drbd.conf
- Create device meta-data:
drbdadm create-md nfshome
- Enable the new resource:
drbdadm attach nfshome drbdadm syncer nfshome drbdadm connect nfshome
On nfs1:
- Connect the new resource:
drbdadm connect nfshome
On nfs2:
- Start initial device synchronisation (ON NFS2 ONLY!):
drbdadm -- --overwrite-data-of-peer primary nfshome
- Check replication status (cat /proc/drbd)
- Add /etc/fstab entry:
/dev/drbd1 /home jfs defaults 0 2
- Mount /home:
mount /home
- Migrate NFS service IP 10.0.5.8 to nfs2:
ip addr add 10.0.5.8/32 dev eth0
- Configure service IP on nfs2 on bootup. Add entry to /etc/networking/interfaces eth0:
up ip addr add 10.0.5.8/32 dev $IFACE
- Start NFS kernel server
[edit] Wrap up
- Migrate udp2log, /usr/local/bin/demux.py from db20 to nfs1 and nfs2
- Write documentation on wikitech about the DRBD setup
[edit] Rollback
If anything goes wrong, the filesystem on /dev/drbd1, or alternatively /dev/sda6 should be in tact and can be mounted. NFS service can then be restored quickly.
