Need help expanding a volume - Veritas Volume Manager

This is a discussion on Need help expanding a volume - Veritas Volume Manager ; I am working with Volume Manager 3.5.2 on a Sun E450 running Solaris 8. I have been trying to figure out how to expand a volume by adding a new drive, but am unsure as to the procedure. I did ...

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  1. Need help expanding a volume


    I am working with Volume Manager 3.5.2 on a Sun E450 running Solaris 8. I
    have been trying to figure out how to expand a volume by adding a new drive,
    but am unsure as to the procedure.

    I did a vxprint of the volume that I am looking to expand and it's results
    are below:

    vxprint -ht -g datadg
    DG NAME NCONFIG NLOG MINORS GROUP-ID
    ST NAME STATE DM_CNT SPARE_CNT APPVOL_CNT
    DM NAME DEVICE TYPE PRIVLEN PUBLEN STATE
    RV NAME RLINK_CNT KSTATE STATE PRIMARY DATAVOLS SRL
    RL NAME RVG KSTATE STATE REM_HOST REM_DG REM_RLNK
    CO NAME CACHEVOL KSTATE STATE
    VT NAME NVOLUME KSTATE STATE
    V NAME RVG/VSET/CO KSTATE STATE LENGTH READPOL PREFPLEX
    UTYPE
    PL NAME VOLUME KSTATE STATE LENGTH LAYOUT NCOL/WID
    MODE
    SD NAME PLEX DISK DISKOFFS LENGTH [COL/]OFF DEVICE
    MODE
    SV NAME PLEX VOLNAME NVOLLAYR LENGTH [COL/]OFF AM/NM
    MODE
    SC NAME PLEX CACHE DISKOFFS LENGTH [COL/]OFF DEVICE
    MODE
    DC NAME PARENTVOL LOGVOL
    SP NAME SNAPVOL DCO

    dg datadg default default 33000 1097476940.65.hughie

    dm datadg01 Disk_11 auto 2048 71124864 -
    dm datadg02 Disk_10 auto 2048 71124864 -
    dm datadg03 Disk_9 auto 2048 71124864 -
    dm datadg04 Disk_8 auto 2048 71124864 -
    dm datadg05 Disk_7 auto 2048 71124864 -
    dm datadg06 Disk_5 auto 2048 71124864 SPARE
    dm datadg07 Disk_13 auto 2048 71124864 NOHOTUSE

    v data2 - ENABLED ACTIVE 284497920 RAID -
    raid5
    pl data2-01 data2 ENABLED ACTIVE 284497920 RAID 5/32
    RW
    sd datadg01-01 data2-01 datadg01 0 71124480 0/0 Disk_11
    ENA
    sd datadg02-01 data2-01 datadg02 0 71124480 1/0 Disk_10
    ENA
    sd datadg03-01 data2-01 datadg03 0 71124480 2/0 Disk_9
    ENA
    sd datadg04-01 data2-01 datadg04 0 71124480 3/0 Disk_8
    ENA
    sd datadg05-01 data2-01 datadg05 0 71124480 4/0 Disk_7
    ENA

    I was attempting to add Disk_13 to the volume using the administrator, but
    every time I do, it comes back and says:

    VxVM vxassist ERROR V-5-1-1178 Volume data2 cannot be extend within the given
    constraints

    I've had the client remove enough data from the array to get it down to less
    than 90% full, since I had seen another messaeg in these forums that said
    this could be an issue, but it still gives te same message. Can somebody
    tell me what the proper method should be for expanding the size of this volume?
    Please CC me direct as I can't easily monitor this newsgroup at this time.

    Any help appreciated!

    markh


  2. Re: Need help expanding a volume

    OK, let's see if you understand the volume.

    > pl data2-01 data2 ENABLED ACTIVE 284497920 RAID 5/32


    This indicates that the plex (the logical part of the volume) is a 5
    column RAID5 plex (with a column size of 32).

    OK, so let's just remind ourselves what a RAID5 (5 column) volume will
    look like:

    Disk_11 Disk_10 Disk_9 Disk_8 Disk_7
    -------------------------------------------------------------
    data data data data parity
    data data data parity data
    data data parity data data
    data parity data parity data
    parity data data data data
    data data data data parity
    data data data parity data
    ...
    ....
    ......



    (Hopefully, you get the idea).
    The main idea behind a RAID5 config. is to be able to lose a disk, and
    still be able to continue.

    The 5 column-layout can also clearly be seen. (each "data" block
    contains 32K of data - the size of the column). This means that if you
    try to read the fisrt 64K from the volume, it will read the first block
    of data on Disk_11 (32K) followed by the first block of data on Disk_10
    (bigger data requests, will just mean Volume Manager has to read from
    the next column, and the next ...... Writing to the volume means that
    the data blocks will be written, and then a parity will be calculated
    per row of data that has changed and then finaly the parity also written
    to the disk containing the parity block for that row)

    OK, so now, let's add your disk_13........

    Where will it go ?
    Are we going to make it a 6-column RAID5 volume now ? Then we need to
    re-layout the volume (not try to grow it). If you want to re-layout, you
    will need some temp space (as you can see it will require a lot of
    moving of data en re-calculating of parity).


    So, in short, if you want to grow the volume, you will have to add 5
    disks to it. In that case, the volume can grow as follows:
    (say we add disk_13,disk_14,disk_15,disk_16 and disk_17)


    Column 1 Column 2 Column 3 Column 4 Column 5
    ================================================== ===========
    Disk_11 Disk_10 Disk_9 Disk_8 Disk_7

    data data data data parity
    data data data parity data
    data data parity data data
    data parity data parity data
    parity data data data data
    data data data data parity
    data data data parity data
    ...
    ....
    ......

    Disk_13 Disk_14 Disk_15 Disk_16 Disk_17

    data data data data parity
    data data data parity data
    data data parity data data
    data parity data parity data
    parity data data data data
    data data data data parity
    data data data parity data
    ...
    ....
    ......



    Still 5 columns and the volume has grown. (It can now hold more data)



    So, just imagine not adding Disk_14,Disk_15,Disk16 and Disk_17 ..... Do
    you still think it will be a 5-column RAID5 volume ? NO !!!


    And that is why Volume Manager keeps on telling you that it can not grow
    the volume within the contraints (of being a 5 column RAID5 volume and
    only 1 more disk to add to columns)





    By the way, loads of people make this mistake. The same applies for a
    STRIPE volume. A STRIPE volume also has columns, but no parity. So if
    you have a 5 column STRIPE volume, you will have to add 5 disks at a
    time to grow the volume.



    Hope that makes it a bit clearer.

    Now, suggestions:

    1. add more disks (an additional 4 disks will do it)
    2. you can do a re-layout of the volume to a 6-column RAID5 volume (not
    suggested as you will need some extra temporary work-space and growing
    it after that will become more and more difficult)






    Mark Holm wrote:
    > I am working with Volume Manager 3.5.2 on a Sun E450 running Solaris 8. I
    > have been trying to figure out how to expand a volume by adding a new drive,
    > but am unsure as to the procedure.
    >
    > I did a vxprint of the volume that I am looking to expand and it's results
    > are below:
    >
    > vxprint -ht -g datadg
    > DG NAME NCONFIG NLOG MINORS GROUP-ID
    > ST NAME STATE DM_CNT SPARE_CNT APPVOL_CNT
    > DM NAME DEVICE TYPE PRIVLEN PUBLEN STATE
    > RV NAME RLINK_CNT KSTATE STATE PRIMARY DATAVOLS SRL
    > RL NAME RVG KSTATE STATE REM_HOST REM_DG REM_RLNK
    > CO NAME CACHEVOL KSTATE STATE
    > VT NAME NVOLUME KSTATE STATE
    > V NAME RVG/VSET/CO KSTATE STATE LENGTH READPOL PREFPLEX
    > UTYPE
    > PL NAME VOLUME KSTATE STATE LENGTH LAYOUT NCOL/WID
    > MODE
    > SD NAME PLEX DISK DISKOFFS LENGTH [COL/]OFF DEVICE
    > MODE
    > SV NAME PLEX VOLNAME NVOLLAYR LENGTH [COL/]OFF AM/NM
    > MODE
    > SC NAME PLEX CACHE DISKOFFS LENGTH [COL/]OFF DEVICE
    > MODE
    > DC NAME PARENTVOL LOGVOL
    > SP NAME SNAPVOL DCO
    >
    > dg datadg default default 33000 1097476940.65.hughie
    >
    > dm datadg01 Disk_11 auto 2048 71124864 -
    > dm datadg02 Disk_10 auto 2048 71124864 -
    > dm datadg03 Disk_9 auto 2048 71124864 -
    > dm datadg04 Disk_8 auto 2048 71124864 -
    > dm datadg05 Disk_7 auto 2048 71124864 -
    > dm datadg06 Disk_5 auto 2048 71124864 SPARE
    > dm datadg07 Disk_13 auto 2048 71124864 NOHOTUSE
    >
    > v data2 - ENABLED ACTIVE 284497920 RAID -
    > raid5
    > pl data2-01 data2 ENABLED ACTIVE 284497920 RAID 5/32
    > RW
    > sd datadg01-01 data2-01 datadg01 0 71124480 0/0 Disk_11
    > ENA
    > sd datadg02-01 data2-01 datadg02 0 71124480 1/0 Disk_10
    > ENA
    > sd datadg03-01 data2-01 datadg03 0 71124480 2/0 Disk_9
    > ENA
    > sd datadg04-01 data2-01 datadg04 0 71124480 3/0 Disk_8
    > ENA
    > sd datadg05-01 data2-01 datadg05 0 71124480 4/0 Disk_7
    > ENA
    >
    > I was attempting to add Disk_13 to the volume using the administrator, but
    > every time I do, it comes back and says:
    >
    > VxVM vxassist ERROR V-5-1-1178 Volume data2 cannot be extend within the given
    > constraints
    >
    > I've had the client remove enough data from the array to get it down to less
    > than 90% full, since I had seen another messaeg in these forums that said
    > this could be an issue, but it still gives te same message. Can somebody
    > tell me what the proper method should be for expanding the size of this volume?
    > Please CC me direct as I can't easily monitor this newsgroup at this time.
    >
    > Any help appreciated!
    >
    > markh
    >


  3. Re: Need help expanding a volume


    Thanks Me!

    That was the answer I had come up with, but not the one that I really wanted.
    I'll go back to the client and tell them that we need to add 4 more disks.
    Seems to me that it would bebetter for them to purchase 5 more larger disks
    and simply build a larger array. There is room in the cabinet to do that,
    and then the old disks could be redeployed for the other volume as needed.

    markh

    Me wrote:
    >OK, let's see if you understand the volume.
    >
    > > pl data2-01 data2 ENABLED ACTIVE 284497920 RAID 5/32

    >
    >This indicates that the plex (the logical part of the volume) is a 5
    >column RAID5 plex (with a column size of 32).
    >
    >OK, so let's just remind ourselves what a RAID5 (5 column) volume will
    >look like:
    >
    >Disk_11 Disk_10 Disk_9 Disk_8 Disk_7
    >-------------------------------------------------------------
    >data data data data parity
    >data data data parity data
    >data data parity data data
    >data parity data parity data
    >parity data data data data
    >data data data data parity
    >data data data parity data
    >...
    >....
    >......
    >
    >
    >
    >(Hopefully, you get the idea).
    >The main idea behind a RAID5 config. is to be able to lose a disk, and
    >still be able to continue.
    >
    >The 5 column-layout can also clearly be seen. (each "data" block
    >contains 32K of data - the size of the column). This means that if you
    >try to read the fisrt 64K from the volume, it will read the first block


    >of data on Disk_11 (32K) followed by the first block of data on Disk_10
    >(bigger data requests, will just mean Volume Manager has to read from
    >the next column, and the next ...... Writing to the volume means that
    >the data blocks will be written, and then a parity will be calculated
    >per row of data that has changed and then finaly the parity also written


    >to the disk containing the parity block for that row)
    >
    >OK, so now, let's add your disk_13........
    >
    >Where will it go ?
    >Are we going to make it a 6-column RAID5 volume now ? Then we need to
    >re-layout the volume (not try to grow it). If you want to re-layout, you


    >will need some temp space (as you can see it will require a lot of
    >moving of data en re-calculating of parity).
    >
    >
    >So, in short, if you want to grow the volume, you will have to add 5
    >disks to it. In that case, the volume can grow as follows:
    >(say we add disk_13,disk_14,disk_15,disk_16 and disk_17)
    >
    >
    >Column 1 Column 2 Column 3 Column 4 Column 5
    >================================================== ===========
    >Disk_11 Disk_10 Disk_9 Disk_8 Disk_7
    >
    >data data data data parity
    >data data data parity data
    >data data parity data data
    >data parity data parity data
    >parity data data data data
    >data data data data parity
    >data data data parity data
    >...
    >....
    >......
    >
    >Disk_13 Disk_14 Disk_15 Disk_16 Disk_17
    >
    >data data data data parity
    >data data data parity data
    >data data parity data data
    >data parity data parity data
    >parity data data data data
    >data data data data parity
    >data data data parity data
    >...
    >....
    >......
    >
    >
    >
    >Still 5 columns and the volume has grown. (It can now hold more data)
    >
    >
    >
    >So, just imagine not adding Disk_14,Disk_15,Disk16 and Disk_17 ..... Do


    >you still think it will be a 5-column RAID5 volume ? NO !!!
    >
    >
    >And that is why Volume Manager keeps on telling you that it can not grow


    >the volume within the contraints (of being a 5 column RAID5 volume and
    >only 1 more disk to add to columns)
    >
    >
    >
    >
    >
    >By the way, loads of people make this mistake. The same applies for a
    >STRIPE volume. A STRIPE volume also has columns, but no parity. So if
    >you have a 5 column STRIPE volume, you will have to add 5 disks at a
    >time to grow the volume.
    >
    >
    >
    >Hope that makes it a bit clearer.
    >
    >Now, suggestions:
    >
    >1. add more disks (an additional 4 disks will do it)
    >2. you can do a re-layout of the volume to a 6-column RAID5 volume (not


    >suggested as you will need some extra temporary work-space and growing
    >it after that will become more and more difficult)
    >
    >
    >
    >
    >
    >
    >Mark Holm wrote:
    >> I am working with Volume Manager 3.5.2 on a Sun E450 running Solaris 8.

    I
    >> have been trying to figure out how to expand a volume by adding a new

    drive,
    >> but am unsure as to the procedure.
    >>
    >> I did a vxprint of the volume that I am looking to expand and it's results
    >> are below:
    >>
    >> vxprint -ht -g datadg
    >> DG NAME NCONFIG NLOG MINORS GROUP-ID
    >> ST NAME STATE DM_CNT SPARE_CNT APPVOL_CNT
    >> DM NAME DEVICE TYPE PRIVLEN PUBLEN STATE
    >> RV NAME RLINK_CNT KSTATE STATE PRIMARY DATAVOLS SRL
    >> RL NAME RVG KSTATE STATE REM_HOST REM_DG REM_RLNK
    >> CO NAME CACHEVOL KSTATE STATE
    >> VT NAME NVOLUME KSTATE STATE
    >> V NAME RVG/VSET/CO KSTATE STATE LENGTH READPOL PREFPLEX
    >> UTYPE
    >> PL NAME VOLUME KSTATE STATE LENGTH LAYOUT NCOL/WID
    >> MODE
    >> SD NAME PLEX DISK DISKOFFS LENGTH [COL/]OFF DEVICE
    >> MODE
    >> SV NAME PLEX VOLNAME NVOLLAYR LENGTH [COL/]OFF AM/NM


    >> MODE
    >> SC NAME PLEX CACHE DISKOFFS LENGTH [COL/]OFF DEVICE
    >> MODE
    >> DC NAME PARENTVOL LOGVOL
    >> SP NAME SNAPVOL DCO
    >>
    >> dg datadg default default 33000 1097476940.65.hughie
    >>
    >> dm datadg01 Disk_11 auto 2048 71124864 -
    >> dm datadg02 Disk_10 auto 2048 71124864 -
    >> dm datadg03 Disk_9 auto 2048 71124864 -
    >> dm datadg04 Disk_8 auto 2048 71124864 -
    >> dm datadg05 Disk_7 auto 2048 71124864 -
    >> dm datadg06 Disk_5 auto 2048 71124864 SPARE
    >> dm datadg07 Disk_13 auto 2048 71124864 NOHOTUSE
    >>
    >> v data2 - ENABLED ACTIVE 284497920 RAID -


    >> raid5
    >> pl data2-01 data2 ENABLED ACTIVE 284497920 RAID 5/32


    >> RW
    >> sd datadg01-01 data2-01 datadg01 0 71124480 0/0 Disk_11
    >> ENA
    >> sd datadg02-01 data2-01 datadg02 0 71124480 1/0 Disk_10
    >> ENA
    >> sd datadg03-01 data2-01 datadg03 0 71124480 2/0 Disk_9
    >> ENA
    >> sd datadg04-01 data2-01 datadg04 0 71124480 3/0 Disk_8
    >> ENA
    >> sd datadg05-01 data2-01 datadg05 0 71124480 4/0 Disk_7
    >> ENA
    >>
    >> I was attempting to add Disk_13 to the volume using the administrator,

    but
    >> every time I do, it comes back and says:
    >>
    >> VxVM vxassist ERROR V-5-1-1178 Volume data2 cannot be extend within the

    given
    >> constraints
    >>
    >> I've had the client remove enough data from the array to get it down to

    less
    >> than 90% full, since I had seen another messaeg in these forums that said
    >> this could be an issue, but it still gives te same message. Can somebody
    >> tell me what the proper method should be for expanding the size of this

    volume?
    >> Please CC me direct as I can't easily monitor this newsgroup at this time.
    >>
    >> Any help appreciated!
    >>
    >> markh
    >>



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