<\/h2>\n
<\/p>\n
- <\/p>\n
- 1. Volume Manager
Objects<\/a><\/strong> <\/a> <\/strong><\/dt>\n<\/p>\n
- 1.1 Disks <\/a><\/dd>\n
<\/p>\n
- 1.2 Disk groups<\/a><\/dd>\n
<\/p>\n
- 1.3 Volume Manager disks<\/a><\/dd>\n
<\/p>\n
- 1.4 Subdisks<\/a><\/dd>\n
<\/p>\n
- 1.5 Plexes<\/a><\/dd>\n
<\/p>\n
- 1.6 Volumes<\/a><\/dd>\n
<\/p>\n
- 1.7 Volume
Manger Objects & their Relationship<\/a><\/dd>\n<\/p>\n
- 2. Volume
Manager Configuration ( options menu)<\/a><\/strong><\/dt>\n<\/p>\n
- 2.1 Add or initialize one or
more disks <\/a><\/dd>\n<\/p>\n
- 2.2
Encapsulate one or more disks <\/a><\/dd>\n<\/p>\n
- 2.3
Remove a disk <\/a><\/dd>\n<\/p>\n
- 2.4
Remove a disk for replacement<\/a><\/dd>\n<\/p>\n
- 2.5
Replace a failed or removed
disk <\/a><\/dd>\n<\/p>\n
- 2.6
Mirror volumes on a disk<\/a><\/dd>\n<\/p>\n
- 2.7
Move volumes from a disk <\/a><\/dd>\n<\/p>\n
- 2.8
Enable access to
(import) a disk group<\/a><\/dd>\n<\/p>\n
- 2.9
Remove access to
(deport) a disk group <\/a><\/dd>\n<\/p>\n
- 2.10
Enable (online) a disk device <\/a><\/dd>\n<\/p>\n
- 2.11
Disable (offline) a disk device <\/a><\/dd>\n<\/p>\n
- 2.12
Mark a disk as a spare
for a disk group<\/a><\/dd>\n<\/p>\n
- 2.13
Turn off the spare flag on a
disk <\/a><\/dd>\n<\/p>\n
About Veritas volume manager :<\/font><\/strong><\/p>\n
Veritas Volume Manager is a software product from veritas Inc. and it is
used to manage disk storage .<\/p>\n<\/p>\n
The main features of volume manager are following :<\/p>\n
<\/p>\n
1.<\/strong> Allows creation of logical volumes spanning over multiple disks.
This overcomes the physical limit of the disk .<\/p>\n<\/p>\n
2. <\/strong>Provides high availability storage solutions through RAID
,Mirroring of disks .<\/p>\n<\/p>\n
3. <\/strong>Provides fail over features by providing transferable disk group
ownership between systems.<\/p>\n<\/p>\n
4.<\/strong> Dynamic reconfiguration of disk storage in an online system state.
what is veritas volume manager .<\/p>\n<\/p>\n
The following article describes the volume manager
objects and configuration of these objects using a text menu based
utility called vxdiskadm .<\/p>\n<\/a>1.0 Volume Manager
Objects <\/strong><\/h4>\n<\/a>Disks<\/font><\/u><\/strong><\/p>\n
Disks are referred in volume
manager by two terms – device name and disk name . The device name
specifies controller , target id and slice of the disk . Disk name is the common
name given to the device name as an easy to remember name .<\/p>\nFor example device name
c2t3dos2 represents controller number 2 , target id 3 , disk group 0
and slice 2 and disk01 may be its disk name . While device name is system dependent
based on controller and disk id the disk
name is user defined . <\/p>\n<\/a>Disk groups :<\/u><\/strong><\/p>\n
<\/p>\n
- <\/p>\n
- \n
A disk group<\/em> is a collection of volume manager disks grouped together to hold
the data . All the configuration changes made to a disk group are applied
to the disks in that disk group only. <\/p>\n<\/li>\n- \n
Volume Manager objects cannot span disk groups i.e. all the operations
on a
particular disk group remains confined to that particular group . <\/p>\n<\/li>\n- \n
Disk groups enable high availability as these can be
shared by two or more hosts but can be accessed by only one host at a time.
In two hosts and a shared storage situation one host can take over the ownership of the
disk groups and
drives in case other host fails.<\/span><\/p>\n<\/li>\n<\/ul>\n<\/p>\n
<\/a>Volume Manager disks<\/u><\/strong><\/p>\n
- <\/p>\n
- \n
Adding physical disks to the volume manager results in
creation of public and private region in the disk by the volume
manager .The public region is the disk space available for volume space and
the private region stores the configuration information. <\/p>\n<\/li>\n - \n
A Volume Manager disks are created from the public region of a
physical disk that is under Volume Manager control. Each volume manager disk
corresponds to one physical disk. <\/p>\n<\/li>\n - \n
A volume manager disk is given a disk media name when it is added to a disk
group which can be default or unique user defined.. <\/p>\n<\/li>\n - \n
Once a volume manager disk is assigned a disk media name, the disk is no longer
referred to by its physical address of c#t#d#<\/font>.
The physical address of c#t#d#<\/font>
becomes known as the disk access record.<\/p>\n<\/li>\n<\/ul>\n<\/p>\n
<\/a>Subdisks<\/strong><\/u><\/p>\n
<\/p>\n
- <\/p>\n
- \n
A subdisk is a subsection of a disk's public region and is the
smallest unit of storage in Volume Manager. <\/p>\n<\/li>\n - \n
A subdisk is defined by an offset and a length in sectors on a
volume manager disk. <\/p>\n<\/li>\n - \n
A volume manager disk can contain multiple subdisks but subdisks cannot
overlap or share the same portions of a volume manager disk. <\/p>\n<\/li>\n - \n
volume manager disk space that is not reserved or that is not part of a subdisk is
free space. You can use free space to create new subdisks.<\/p>\n<\/li>\n<\/ul>\n<\/p>\n
A subdisk is similar to a partition but with following differences :<\/p>\n
<\/p>\n
- <\/p>\n
- \n
The maximum number of partitions to a disk is eight. <\/p>\n<\/li>\n
- \n
There is no theoretical limit to number of subdisks that can be attached
to a single plex, but
it has been limited to a default value of 4096. If required, this default
can be changed, using the vol_subdisk_num<\/font>
tunable parameter.<\/p>\n<\/li>\n<\/ul>\n<\/p>\n
<\/p>\n<\/a>Plexes<\/strong><\/u><\/p>\n
<\/p>\n
- <\/p>\n
- \n
A plex<\/strong> is a
structured or ordered collection of subdisks that represents one copy of
the data in a volume. A plex<\/strong>
consists of one or more subdisks located on one or more physical disks. <\/p>\n<\/li>\n- \n
A plex
is also
called a mirror. The terms
plex and mirror
can be used interchangeably, even though a plex
is only one copy of the data. The terms
"mirrored" or "mirroring" imply two or more copies of
data. <\/p>\n<\/li>\n- \n
The length of a plex
is determined by the last block that can be read or written on the last
subdisk in the plex. <\/p>\n<\/li>\n- \n
The default naming convention for plexes in a volume is volumename<\/font><\/em>-##<\/font>.
The default plex
name consists of the volume name, a hyphen, and a two-digit number <\/p>\n<\/li>\n<\/ul>\n<\/div>\n
<\/p>\n
<\/p>\n<\/a>Volumes<\/u><\/strong><\/p>\n
<\/p>\n
- <\/p>\n
- \n
A volume is composed of one or more plexes not restricted by the
physical size of the disk. <\/p>\n<\/li>\n - \n
A volume can span across multiple disks. <\/p>\n<\/li>\n
- \n
Volume Manager uses the default naming convention vol##<\/font>
for volumes, where ## represents a two-digit number but can be user defined
as per requirement. <\/p>\n<\/li>\n<\/ul>\n<\/p>\n
<\/a>Volume
Manager Objects and Their Relationship<\/strong><\/p>\n<\/p>\n
- \n
- \n
- \n
- \n
- \n
- 1.1 Disks <\/a><\/dd>\n
![\"\"](\"http:\/\/lookit.org\/guppy\/vxvm_P_fichiers\/vxvm1.jpg\")
<\/td>\n![\"\"](\"http:\/\/lookit.org\/guppy\/vxvm_P_fichiers\/vxvm2.jpg\")
<\/td>\n<\/tr>\n![\"\"](\"http:\/\/lookit.org\/guppy\/vxvm_P_fichiers\/volume.jpg\")
<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n