[SunHELP] Veritas Volume Manager Question

Henry Buford III sunhelp at sunhelp.org
Fri Feb 2 11:13:35 CST 2001


How to distinguish between a concat pro and a stripe pro layout of a layered
volume based on the vxprint output.

TechNote ID: 194660	Last Updated: April 26 2000 07:09 PM
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Symptom: 
How to distinguish between a concat pro and a stripe pro layout of a layered
volume based on the vxprint output. 
Solution: 
VERITAS Volume Manager 3.0 or higher supports layered volumes. A layered
volume is built on top of volumes. The layered volume structure tolerates
failure better and has greater redundancy than the standard volume
structure. In previous releases,  whenever mirroring was used,  the
mirroring had to happen  above  striping  or concatenation.  Now there can
be mirroring both above and below striping and concatenation. 
These new layouts enhance redundancy and reduce recovery time in case of an
error.  In a mirror-stripe layout,  if a disk fails,  the entire plex is
detached, thereby losing redundancy on the entire volume.  When the disk is
replaced, the entire plex must be brought up to date.  Recovering the entire
plex can take a substantial amount of time.  If a disk fails in a 
stripe-mirror  layout,  only the failing subdisk must be detached, and only
that portion of the volume loses redundancy.
When the disk is replaced,  only a portion of the volume needs to be
recovered.

Concat Pro:

A concatenated volume that is large enough to have multiple subdisks would
mirror each subdisk individually. A simple mirrored volume with multiple
copies of data on multiple disks. The concat pro volume contains a plex
which holds several volumes which mirror the data. 

1. The example below is for a concat pro volume that has 2 mirrors.
# vxassist -g mmdg make catpro 5m layout=concat-mirror,nolog 

v  catpro       fsgen        ENABLED  ACTIVE   10240    SELECT    -
pl catpro-03    catpro       ENABLED  ACTIVE   10240    CONCAT    -
RW
sv catpro-S01   catpro-03    catpro-L01 1      10240    0         2/2
ENA

v  catpro-L01   fsgen        ENABLED  ACTIVE   10240    SELECT    -
pl catpro-P01   catpro-L01   ENABLED  ACTIVE   10240    CONCAT    -
RW
sd mmdisk04-03  catpro-P01   mmdisk04 10640    10240    0         c1t3d1
ENA
pl catpro-P02   catpro-L01   ENABLED  ACTIVE   10240    CONCAT    -
RW
sd mmdisk05-03  catpro-P02   mmdisk05 10640    10240    0         c1t5d0
ENA

2.  The example below is for a concat pro volume that has 3 mirrors.
# vxassist -g mmdg make catpro1 5m layout=concat-mirror,nolog nmirror=3

v  catpro1      fsgen        ENABLED  ACTIVE   10240    SELECT    -
pl catpro1-04   catpro1      ENABLED  ACTIVE   10240    CONCAT    -
RW
sv catpro1-S01  catpro1-04   catpro1-L01 1     10240    0         3/3
ENA

v  catpro1-L01  fsgen        ENABLED  ACTIVE   10240    SELECT    -
pl catpro1-P01  catpro1-L01  ENABLED  ACTIVE   10240    CONCAT    -
RW
sd mmdisk01-04  catpro1-P01  mmdisk01 16240    10240    0         c1t5d2
ENA
pl catpro1-P02  catpro1-L01  ENABLED  ACTIVE   10240    CONCAT    -
RW
sd mmdisk07-05  catpro1-P02  mmdisk07 16240    10240    0         c1t4d2
ENA
pl catpro1-P03  catpro1-L01  ENABLED  ACTIVE   10240    CONCAT    -
RW
sd mmdisk06-06  catpro1-P03  mmdisk06 16800    10240    0         c1t3d0
ENA


Stripe Pro:

Putting mirroring below striping mirrors each column of  the stripe.  If the
stripe is large enough to have multiple subdisks per column,  each subdisk
can be individually mirrored. A Stripe Pro is a stripe + mirror volume with
multiple copies of data across multiple disks. The stripe pro volume
contains a plex with several subvolumes. Each subvolume corresponds to a
column or stripe. Each subvolume contains a stripe and its mirror. Each
mirror covers a smaller area of storage space, so recovery is quicker than
with a standard stripe + mirror volume.

1. The example below is for a stripe pro volume with 3 stripes and mirrored.
# vxassist -g mmdg make strpro 5m layout=stripe-mirror,nolog stripeunit=128
ncolumns=3

v  strpro       fsgen        ENABLED  ACTIVE   10240    SELECT    strpro-03
pl strpro-03    strpro       ENABLED  ACTIVE   10368    STRIPE    3/128
RW
sv strpro-S01   strpro-03    strpro-L01 1      3456     0/0       2/2
ENA
sv strpro-S02   strpro-03    strpro-L02 1      3456     1/0       2/2
ENA
sv strpro-S03   strpro-03    strpro-L03 1      3456     2/0       2/2
ENA

v  strpro-L01   fsgen        ENABLED  ACTIVE   3456     SELECT    -
pl strpro-P01   strpro-L01   ENABLED  ACTIVE   3456     CONCAT    -
RW
sd mmdisk01-04  strpro-P01   mmdisk01 14560    3456     0         c1t5d2
ENA
pl strpro-P02   strpro-L01   ENABLED  ACTIVE   3456     CONCAT    -
RW
sd mmdisk02-04  strpro-P02   mmdisk02 14560    3456     0         c1t2d0
ENA

v  strpro-L02   fsgen        ENABLED  ACTIVE   3456     SELECT    -
pl strpro-P03   strpro-L02   ENABLED  ACTIVE   3456     CONCAT    -
RW
sd mmdisk07-05  strpro-P03   mmdisk07 14560    3456     0         c1t4d2
ENA
pl strpro-P04   strpro-L02   ENABLED  ACTIVE   3456     CONCAT    -
RW
sd mmdisk04-04  strpro-P04   mmdisk04 14560    3456     0         c1t3d1
ENA

v  strpro-L03   fsgen        ENABLED  ACTIVE   3456     SELECT    -
pl strpro-P05   strpro-L03   ENABLED  ACTIVE   3456     CONCAT    -
RW
sd mmdisk06-06  strpro-P05   mmdisk06 15120    3456     0         c1t3d0
ENA
pl strpro-P06   strpro-L03   ENABLED  ACTIVE   3456     CONCAT    -
RW
sd mmdisk05-04  strpro-P06   mmdisk05 14560    3456     0         c1t5d0
ENA


compare this to a regular striped + mirror volume with 3 stripes and
mirrored:
# vxassist  -g mmdg   make strmirr 5m layout=striped,nolog nmirror=2
stripeunit=128 ncolumn=3

v  strmirr      fsgen        ENABLED  ACTIVE   10240    SELECT    -
pl strmirr-01   strmirr      ENABLED  ACTIVE   11856    STRIPE    3/128
RW
sd mmdisk01-01  strmirr-01   mmdisk01 10640    3920     0/0       c1t5d2
ENA
sd mmdisk07-03  strmirr-01   mmdisk07 10640    3920     1/0       c1t4d2
ENA
sd mmdisk06-01  strmirr-01   mmdisk06 11200    3920     2/0       c1t3d0
ENA
pl strmirr-02   strmirr      ENABLED  ACTIVE   11856    STRIPE    3/128
RW
sd mmdisk02-02  strmirr-02   mmdisk02 10640    3920     0/0       c1t2d0
ENA
sd mmdisk04-02  strmirr-02   mmdisk04 10640    3920     1/0       c1t3d1
ENA
sd mmdisk05-02  strmirr-02   mmdisk05 10640    3920     2/0       c1t5d0
ENA

Acknowledgments: 
see also man page for vxassist 

TechNote Summary:

TechNote Title:	How to distinguish between a concat pro and a stripe pro
layout of a layered volume based on the vxprint output.
TechNote ID:	194660
Last Updated:	April 26 2000 07:09 PM

This information in this TechNote applies to:

Products:	Volume Manager for UNIX   	3.0, 3.0.1, 3.0.2

Subject:	Application - How To
Languages:	English
Operating Systems:	Solaris   	2.51, 2.6, 2.7, 2.8



VERITAS Software, 1600 Plymouth Street, Mountain View, California 94043
World Wide Web: http://www.veritas.com[NL]Tech Support Web:
http://support.veritas.com[NL]E-Mail for Classic VERITAS Products:
support at veritas.com[NL]E-Mail for Classic Seagate Software Products:
helpdesk at support.veritas.com[NL]FTP:ftp://ftp.support.veritas.com or
http://ftp.support.veritas.com


Henry Buford, III 
MCP, MCP+I, MCSE, Sun Certified Solaris Admin I

VERITAS Software
Senior Technical Support Analyst 
VERITAS Technical Services
Tech Support: 1-800-634-4747 
http://support.veritas.com 
"Ask me about SupportNOW!" -> http://supportnow.support.veritas.com"


-----Original Message-----
From: Ann Waters [mailto:Ann.Waters at kp.org]
Sent: Friday, February 02, 2001 10:48 AM
To: sunhelp
Subject: [SunHELP] Veritas Volume Manager Question

Hi Listers,

Can anyone tell me how to determine if some disks/disk groups under control
of the Veritas Volume Manager are mirrored?
I got a box dumped on me that has all of the filesystems under the Volume
Manager and I can't seem to figure out the
vx<whatever> man pages to determine how to see if the filesystems are
mirrored.  (And here I thought I was doing great
getting DiskSuite figured out.  I'm an old dog and am having trouble
learning new tricks!)

Thanks in advance!

Ann Waters
Kaiser Permanente
Silver Spring, MD
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