September 14, 2004
在RAC环境中如何管理日志(redolog file)组
作者:eygle
出处:http://blog.eygle.com
本文简单介绍在RAC裸设备环境下如何管理日志文件(redolog file)
本文环境:Oracle9i Rac + VCS4.0 + VxVM4.0 + Solaris9.0 + SunFire210
1.首先可以查看当前裸设备情况
# vxprint
Disk group: oradg
TY NAME ASSOC KSTATE LENGTH PLOFFS STATE TUTIL0 PUTIL0
dg oradg oradg - - - - - -
dm oradg01 c2t0d2s2 - 244143872 - - - -
v ctlfile1 gen ENABLED 204800 - ACTIVE - -
pl ctlfile1-01 ctlfile1 ENABLED 204800 - ACTIVE - -
sd oradg01-13 ctlfile1-01 ENABLED 204800 0 - - -
v ctlfile2 gen ENABLED 204800 - ACTIVE - -
pl ctlfile2-01 ctlfile2 ENABLED 204800 - ACTIVE - -
sd oradg01-14 ctlfile2-01 ENABLED 204800 0 - - -
v redo101 gen ENABLED 204800 - ACTIVE - -
pl redo101-01 redo101 ENABLED 204800 - ACTIVE - -
sd oradg01-04 redo101-01 ENABLED 204800 0 - - -
v redo102 gen ENABLED 204800 - ACTIVE - -
pl redo102-01 redo102 ENABLED 204800 - ACTIVE - -
sd oradg01-05 redo102-01 ENABLED 204800 0 - - -
v redo103 gen ENABLED 204800 - ACTIVE - -
pl redo103-01 redo103 ENABLED 204800 - ACTIVE - -
sd oradg01-06 redo103-01 ENABLED 204800 0 - - -
v redo201 gen ENABLED 204800 - ACTIVE - -
pl redo201-01 redo201 ENABLED 204800 - ACTIVE - -
sd oradg01-07 redo201-01 ENABLED 204800 0 - - -
v redo202 gen ENABLED 204800 - ACTIVE - -
pl redo202-01 redo202 ENABLED 204800 - ACTIVE - -
sd oradg01-08 redo202-01 ENABLED 204800 0 - - -
v redo203 gen ENABLED 204800 - ACTIVE - -
pl redo203-01 redo203 ENABLED 204800 - ACTIVE - -
sd oradg01-09 redo203-01 ENABLED 204800 0 - - -
v spfile gen ENABLED 204800 - ACTIVE - -
pl spfile-01 spfile ENABLED 204800 - ACTIVE - -
sd oradg01-12 spfile-01 ENABLED 204800 0 - - -
v srvcfg gen ENABLED 1024000 - ACTIVE - -
pl srvcfg-01 srvcfg ENABLED 1024000 - ACTIVE - -
sd oradg01-15 srvcfg-01 ENABLED 1024000 0 - - -
v system gen ENABLED 1638400 - ACTIVE - -
pl system-01 system ENABLED 1638400 - ACTIVE - -
sd oradg01-01 system-01 ENABLED 1638400 0 - - -
v temp gen ENABLED 2048000 - ACTIVE - -
pl temp-01 temp ENABLED 2048000 - ACTIVE - -
sd oradg01-02 temp-01 ENABLED 2048000 0 - - -
v undo11 gen ENABLED 16777216 - ACTIVE - -
pl undo11-01 undo11 ENABLED 16777216 - ACTIVE - -
sd oradg01-10 undo11-01 ENABLED 2048000 0 - - -
sd oradg01-17 undo11-01 ENABLED 14729216 2048000 - - -
v undo21 gen ENABLED 2048000 - ACTIVE - -
pl undo21-01 undo21 ENABLED 2048000 - ACTIVE - -
sd oradg01-11 undo21-01 ENABLED 2048000 0 - - -
v users gen ENABLED 16777216 - ACTIVE - -
pl users-01 users ENABLED 16777216 - ACTIVE - -
sd oradg01-03 users-01 ENABLED 2048000 0 - - -
sd oradg01-16 users-01 ENABLED 14729216 2048000 - - -
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2.分配新的裸设备并设置相应的权限
这一步需要以root身份执行
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# vxassist -g oradg -U gen make redo104 100m
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3.重新规划redolog file组
$ sqlplus "/ as sysdba"
SQL*Plus: Release 9.2.0.4.0 - Production on Tue Sep 14 10:02:47 2004
Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
Connected to:
Oracle9i Enterprise Edition Release 9.2.0.4.0 - 64bit Production
With the Real Application Clusters option
JServer Release 9.2.0.4.0 - Production
SQL> set linesize 120
SQL> select * from v$log;
GROUP# THREAD# SEQUENCE# BYTES MEMBERS ARC STATUS FIRST_CHANGE# FIRST_TIM
---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ---------
1 1 6313 52428800 1 NO ACTIVE 3193855 14-SEP-04
2 1 6312 52428800 1 NO INACTIVE 3191691 14-SEP-04
5 1 6314 52428800 1 NO CURRENT 3196041 14-SEP-04
3 2 17 10485760 1 NO CURRENT 3016310 14-SEP-04
4 2 16 10485760 1 NO INACTIVE 1619198 13-SEP-04
SQL> alter database add logfile thread 1 group 6 ('/dev/vx/rdsk/oradg/redo104') size 90M;
Database altered.
SQL> alter database add logfile thread 1 group 7 ('/dev/vx/rdsk/oradg/redo105') size 90M;
Database altered.
SQL> select * from v$log;
GROUP# THREAD# SEQUENCE# BYTES MEMBERS ARC STATUS FIRST_CHANGE# FIRST_TIM
---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ---------
1 1 6316 52428800 1 NO INACTIVE 3200415 14-SEP-04
2 1 6315 52428800 1 NO INACTIVE 3198233 14-SEP-04
5 1 6317 52428800 1 NO ACTIVE 3202621 14-SEP-04
6 1 6318 94371840 1 NO CURRENT 3204811 14-SEP-04
7 1 0 94371840 1 YES UNUSED 0
3 2 17 10485760 1 NO CURRENT 3016310 14-SEP-04
4 2 16 10485760 1 NO INACTIVE 1619198 13-SEP-04
7 rows selected.
SQL> alter database drop logfile group 5;
Database altered.
SQL> alter database add logfile thread 1 group 5 ('/dev/vx/rdsk/oradg/redo103') size 90M;
Database altered.
....
SQL> select *from v$log;
GROUP# THREAD# SEQUENCE# BYTES MEMBERS ARC STATUS FIRST_CHANGE# FIRST_TIM
---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ---------
1 1 6327 94371840 1 NO INACTIVE 3238534 14-SEP-04
2 1 6329 94371840 1 NO CURRENT 3246417 14-SEP-04
5 1 0 94371840 1 YES UNUSED 0
6 1 6328 94371840 1 NO ACTIVE 3242482 14-SEP-04
7 1 6326 94371840 1 NO INACTIVE 3234597 14-SEP-04
3 2 17 10485760 1 NO CURRENT 3016310 14-SEP-04
4 2 16 10485760 1 NO INACTIVE 1619198 13-SEP-04
7 rows selected.
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Posted by eygle at 7:59 PM | Comments (1)
Veritas Volume Manager(VxVM)-vxassist命令手册
作者:eygle
出处:http://blog.eygle.com
vxassist是VxVM中非常重要的一个工具,使用非常频繁,我这里给出一个命令手册,并作了一些简单的翻译和注释,仅供参考.
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3.1 Shrinking to a Given Length
3.2 Shrinking by a Given Length
4. Removing a Volume
5. Mirroring a Volume
5.1 Creating & Mirroring a New Volume
5.2 Mirroring an Existing Volume
5.3 Mirroring All Volumes
6.Removing a Mirror
7.Adding a RAID-5 Log
8.Adding a DRL Log
9.Removing a RAID-5 Log
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vxassist工具是VxVM中用于进行卷管理的工具,可以用于创建卷、增加镜像、扩展或者收缩存在的卷等,是非常重要的一个工具.
The vxassist utility in Veritas Volume Manager is used to create volumes, add mirrors and logs to existing volumes, extend and shrink existing volumes, provides for the migration of data from a specified set of disks, and provides facilities for the on-line backup of existing volumes.
vxassist在创建卷组时,如果不指定,缺省的会把卷分配给rootdg(note:在VxVM4.0中rootdg不再必须,但是你可以指定一个default dg具有类似的功能).
vxassist的缺省单位是blocks,但是你可以指定K 或 M 或 G 为单位,这都是合法的.The default behavior of vxassist is to create volumes in the rootdg diskgroup if diskgroup is not specified . The default length is taken as number of blocks but this can be specified in Kilobytes or Megabytes or Gigabytes.
vxassist <option> <Keyword> volume_name [attributes]
- Commonly used options are given below (See man vxassist for complete list of supported options) -g for specifying diskgroups -b for background operation -d file containing defaults for vxassist if not specified /etc/default/vxassist is used Keywords used are make , mirror , move , growto ,growby ,shrintto ,shirnkby ,snapstart , snapshot ,snapwait Attributes specify volumes layout disks controllar to include exclude etc
Device Nodes :
- Default rootdg disk group.
- Block Device Node /dev/vx/dsk/volume_name
- Raw Device Node /dev/vx/rdsk/volume_name
- Block Device Node /dev/vx/dsk/volume_name
- Other DiskGroups
- Block Device Node /dev/vx/dsk/diskgroup_name/volume_name
- Raw Device Node /dev/vx/rdsk/diskgroup_name/volume_name
- Block Device Node /dev/vx/dsk/diskgroup_name/volume_name
_______________________________________
1.1 Creating a Concatenated Volume
缺省的,vxassist把一个卷组里的所有磁盘统一看待,如果创建的volume大于单个磁盘,那么空间分配自动的跨越磁盘.
By default, vxassist creates a concatenated volume using the space available on a disk or on the number of disks in a diskgroup if the volume size specified is more then the one available on a single disk.
Disks can be specified from a diskgroup for a volume group but if not mentioned available disks are selected by the volume manager.
Command syntax :
· vxassist make volume_name volume_length
- To create a new volume appvol of 100 MB in the default disk group rootdg with available disks:
- · #vxassist make appvol 100m
To create the volume appvol of 100MB on disk03
· #vxassist make appvol 100m disk03
A striped volume contains at least one plex that consists of two or more subdisks located on two or more physical disks.
Command Syntax :
· vxassist make volume_name length layout=stripe
To create a striped volume appvol2 with the default stripe unit size on the default number of disks
· #vxassist make appvol2 100m layout=stripe
To create a striped volume appvol2 100MB striped volume on three specific disks.
· #vxassist make appvol2 100m layout=stripe disk04 disk05 disk06
A RAID-5 volume contains a RAID-5 plex that consists of two or more subdisks located on two or more physical disks. Only one RAID-5 plex can exist per volume. A RAID-5 volume may also contain one or more RAID-5 log plexes, which are used to log information about data and parity being written to the volume.
Command Syntax :
· vxassist make volume_name length layout=raid5
To create the RAID-5 volume appvol4 with the default stripe unit size on the default number of disks with RAID-5 log,
· #vxassist make appvol4 100m layout=raid5.
2. Extending a Volume--扩展一个建好的Volume
Caution : If you plan to use volume size change (grow or shrink ) on a volume with data make sure you have the good backup of the volume available before carrying out such operation .
2.1 Extending a volume up to certain length
Command syntax
· vxassist growto volume_name length
To extend vol3 upto 8000 sectors, type:--例如,扩展vol3到8000个扇区
· #vxassist growto vol3 8000
Note:这里可以指定大小,例如:
vxassist growto redo101 100M
如果使用的是非缺省DG,还需要指定磁盘组:
vxassist -g oradg growto redo101 100M
2.2 Extending by a Given Length
Command Syntax
· vxassist growby volume_name length
To extend volapp by 1000 sectors, type:
· #vxassist growby volapp 1000
Caution - Do not shrink a volume below the size of the file system. If you have a VxFS file system, you can shrink the file system and then shrink the volume. If you do not shrink the file system first, you risk unrecoverable data loss.
Always make sure you have a good backup of the data volume to be shirnked.
3.1 Shrinking to a Given Length
Shrink a volume to a specific length as follows:
· vxassist shrinkto volume_name length
Make sure you do not shrink the volume below the current size of the file system or database using the volume. This command can be safely used on empty volumes.
To shrink volcat to 1300 sectors, type:
· #vxassist shrinkto volcat 1300
3.2 Shrinking by a Given Length
Shrink a volume by a specific length as follows:
· vxassist shrinkby volume_name length
To shrink volcat by 8000 sectors, type:
· #vxassist shrinkby volapp2 8000
Removing a volume requires removing all references to the volumes to be removed like unmounting the volume if mounted and removing its reference from /etc/vfstab .
如果你需要remove一个volume,那么首先你需要stop这个卷组,停止其上的所有活动事务.
An active volume has to be stopped first to stop all the activities to the volume only then it can be removed.
Stopping Volume :
Command Syntax
· vxvol stop volume_name
To stop appvol1
· #vxvol stop appvol1
Removing Volume
Command Syntax
· vxedit -rf rm volume_name
To remove the volume appvol1
· #vxedit -rf rm appvol11
Mirroring allow data to be written simultaneously to two disks so that in case of failure of one disk data is available from the other mirrored disk. Boot disks can be mirriored to provide alternate booting disk .
5.1 Creating & Mirroring a New Volume
Command Syntax :
· vxassist make volume_name length layout=mirror
To create the mirrored volume, appvol22 of 100mb
· #vxassist make appvol22 100m layout=mirror
To create a volume with Dirty Region Logging enabled
· #vxassist make volume_name length layout=mirror,log
5.2 Mirroring an Existing Volume
Command syntax
· vxassist mirror volume_name
Creating a mirror of volume vol44:
· #vxassist mirror vol44
To mirror all existing volumes to available disk space
· /etc/vx/bin/vxmirror -a
Removing a mirror involves first dissociating the plex from its volume and then removing the plex and any associated subdisks completely.The last valid mirror plex associated with a volume cannot be removed.
Dissociate and remove the plex from its volume as follows:
· vxplex -o rm dis plex_name
vxprint -h shows the volume and associated plexes :
Disk group: rootdg TY NAME ASSOC KSTATE LENGTH PLOFFS STATE TUTIL0 PUTIL0 v volm fsgen ENABLED 10240 - ACTIVE - - pl volm-01 volm ENABLED 10240 - ACTIVE - - sd disk01-02 volm-01 - 10240 0 - - - pl volm-02 volm ENABLED 10240 - ACTIVE - - sd disk02-03 volm-02 - 10240 0 - - -
To disassociate and remove volmir-02 from volmir, type:
· #vxplex -o rm dis volm-02
The output of vxprint -h for volm now shows volume volm with only one plex::
Disk group: rootdg TY NAME ASSOC KSTATE LENGTH PLOFFS STATE TUTIL0 PUTIL0 v volm fsgen ENABLED 10240 - ACTIVE - - pl volm-01 volmir ENABLED 10240 - ACTIVE - - sd disk01-02 volmir-01 - 10240 0 - - -
A RAID-5 log maintains a copy of the data and parity being written to the volume at any given time. If a system failure occurs, VxVM can replay the RAID-5 log to resynchronize the volume. This copies the data and parity that was being written at the time of failure from the log to the appropriate areas of the RAID-5 volume.
RAID-5 log plexes are used to log information about data and parity being written to the raid volume. A log plex is created for the volume by default when a raid volume is created but additional ones can be added by following command .
· vxassist addlog name_of_raid5_vol
Dirty region logging (DRL) is used with mirrored volume layouts. DRL keeps track of the regions that have changed due to I/O writes to a mirrored volume. Prior to every write, a bitmap is written to a log to record the area of the disk that is being changed. In case of system failure, DRL uses this information to recover only the portions of the volume that need to be recovered.
To put Dirty Region Logging into effect for a volume, a log subdisk must be added to that volume and the volume must be mirrored. Only one log subdisk can exist per plex.
The following example creates a log for the mirrored volume vol03:
· #vxassist addlog vol03
When vxassist is used to add a log subdisk to a volume, a log plex is also created to contain the log subdisk, by default.
Once created, the plex containing a log subdisk can be treated as a regular plex. Data subdisks can be added to the log plex. The log plex and log subdisk can be removed using the same procedures used to remove ordinary plexes and subdisks.
Removing a RAID-5 log involves first dissociating the log from its volume and then removing the log and any associated subdisks completely.
Dissociate the log from its volume as follows:
· #vxplex -o rm dis plex_name
To identify the log plex, use the command:
· vxprint -ht raid5_volume_name
To disassociate the log plex volrd-02 from volrd, type:
· #vxplex -o rm dis volrd-02
The output of vxprint -h for volrd now shows:
Disk group: rootdg TY NAME ASSOC KSTATE LENGTH PLOFFS STATE TUTIL0 PUTIL0 v volrd raid5 ENABLED 32 - ACTIVE - - pl volrd-01 volrd ENABLED 32 - ACTIVE - - sd disk01-02 volrd-01 - 32 0 - - - sd disk02-03 volrd-01 - 32 0 - - -
10. Preparing a Volume for Online Backup
Volume manager provides an easy way to take backup of the online data by creating an offline snapshot mirror of the volume .
The vxassist snapstart operation creates a write-only backup mirror, which is attached to and synchronized with the volume to be backed up and later detached and made offline by vxassist snapshot command . The snapshot volume can be used by backup utilities while the original volume continues to be available for applications and users.
The volume backup method described here does not apply to RAID-5 volumes.
Backing up a volume with vxassist involves the following procedure
Create a snapshot mirror
snapstart starts creating a online snapshot mirror of the volume using the available disk space . The snapshot is completed with vxassist snapshot command when offline snapshot volume is created with a userdefined name .
Command Syntax:
- vxassist snapstart volume_name
To create a snapshot mirror of a volume called vol8, type
- #vxassist snapstart vol8
Create a snapshot volume
Command Syntax
vxassist snapshot volume_name new_volume_name
To create a snapshot volume of vol8, type:
#vxassist snapshot vol8 snapvol8
You can now back up the snapshot volume by whatever means you prefer. To avoid wasting space, you can then remove the snapshot volume, which occupies as much space as the original volume
11 Displaying Volume Configuration Information
The vxprint command can be used to display information about how a volume is configured.
Display the volume, mirror, and subdisk record information for all volumes as follows:
#vxprint -ht
Disk group: rootdg DG NAME NCONFIG NLOG MINORS GROUP-ID DM NAME DEVICE TYPE PRIVLEN PUBLEN STATE V NAME USETYPE KSTATE STATE LENGTH READPOL PREFPLEX PL NAME VOLUME KSTATE STATE LENGTH LAYOUT NCOL/WID MODE SD NAME PLEX DISK DISKOFFS LENGTH [COL/]OFF DEVICE MODE dg rootdg 759096729.1025.tweety dm disk10 c1t0d0s2 sliced 559 1044400 - dm disk20 c2t0d0s2 sliced 559 1044400 - v pubs fsgen ENABLED ACTIVE 2288 SELECT - pl pubs-01 pubs ENABLED ACTIVE 2288 CONCAT - RW sd disk10-01 pubs-01 disk10 0 2288 0 c0t0d0 ENA v vol8 fsgen ENABLED ACTIVE 20480 SELECT - pl vol8-01 vol8 ENABLED ACTIVE 20480 CONCAT - RW sd disk10-02 vol8-0 disk10 2288 20480 0 c0t1d0 ENA |
where dg is a disk group, dm is a disk, v is a volume, pl is a plex, and sd is a subdisk. The top few lines indicate the headers that match each type of output line that follows. Each volume is listed along with its associated plex(es) and subdisk(s).
Display volume-related information for a specific volume as follows:
#vxprint -t volume_name
To display information about vol8, type:
#vxprint -t vol8
Posted by eygle at 10:52 AM | Comments (3)