3 Replies Latest reply: Sep 20, 2012 2:50 AM by ozgurumut RSS

    ASM Disk size not correct

    ozgurumut
      Hi All,

      I face to interesting event in ASM. Summary of Problem;

      +FRA size 400GB and Free Space 175GB ,result of lsdg command like that on below;

      ASCMD> lsdg
      State Type Rebal Unbal Sector Block AU Total_MB Free_MB Req_mir_free_MB Usable_file_MB Offline_disks Name
      MOUNTED EXTERN N N 512 4096 1048576 409600 175717 0 175717 0 FRA/
      MOUNTED EXTERN N N 512 4096 1048576 2252800 440059 0 440059 0 DATA/

      According to "du" command result , +FRA of size 265GB
      ASMCMD> cd +fra
      ASMCMD> du
      Used_MB Mirror_used_MB
      26515 26515

      So two value is different. I thit it should be same because we are queried same area. Do you know why two infos are different ?

      Perhalps it can be help response of your response that according to result of in"select * from v$flash_recovery_area_usage;" All FRA in SQL*Plus .

      SQL> select * from v$flash_recovery_area_usage;

      FILE_TYPE PERCENT_SPACE_USED PERCENT_SPACE_RECLAIMABLE NUMBER_OF_FILES
      ------------ ------------------ ------------------------- ---------------
      CONTROLFILE 0 0 0
      ONLINELOG 0 0 0
      ARCHIVELOG .92 0 8
      BACKUPPIECE 0 0 0
      IMAGECOPY 0 0 0
      FLASHBACKLOG 5.84 0 118

      Thanks...
        • 1. Re: ASM Disk size not correct
          Levi Pereira
          Hi,

          Unbalanced disk can cause disk lacking sufficient free space makes it impossible to do any allocation in a disk group because every file must be evenly allocated across all disks per ASM stripping policy.

          Unbalanced disk configuration and certain operations on ASM disks can create this type of problem. The problem frequently should be resolved after a succesfull rebalance as far as all disks have the same storage capacity and there is no underlying hardware problems.
          The most common reasons can be as follows:

          1- Capacity of disks within ASM diskgroup are different
          2- ASM instance is shutdowned normal/immediate before a rebalance is completed.
          3- Disk is DROPPING / HUNG state
          4- After an add disk command the rebalance is still in place

          Also you can try:
          ALTER DISKGROUP FRA CHECK ALL REPAIR;
          P.S: Make sure you have these files on FRA was backed up to a safe location.

          Regards,
          Levi Pereira
          • 2. Re: ASM Disk size not correct
            onedbguru
            what does the following command show:

            Make sure all of the devices that make up a particular diskgroup are the same size.

            col path format a50
            select group_number,path,total_mb from v$asm_disk order by 1;

            Let's see our diskgroup utilization:

            col "USED%" format 999.99
            select group_number, sum(total_mb) TOTL_MB, sum(free_mb) FREE_MB, sum(total_mb)-sum(free_mb) USED_MB, (sum(total_mb)-sum(free_mb))/sum(total_mb) "USED%" from v$asm_disk group by group_number order by group_number;
            • 3. Re: ASM Disk size not correct
              ozgurumut
              Hi Friends;

              I executed this query and I realized two FRA disks and they didn't rebalanced.

              SQL> select a.name,a.TOTAL_MB, a.FREE_MB, a.PATH from v$asm_disk_stat a,
              v$asm_diskgroup_stat g where a.GROUP_NUMBER=g.GROUP_NUMBER order by name;

              NAME TOTAL_MB FREE_MB PATH
              --------------- ---------- ---------- ----------------------------------------
              FRA_0000 204800 0 /dev/mapper/B_ASMDISK8
              FRA_0001 204800 176319 /dev/mapper/RB_ASMDISK13
              SDG_0000 204800 39969 /dev/mapper/RB_ASMDISK1
              SDG_0001 204800 39977 /dev/mapper/RB_ASMDISK2
              SDG_0002 204800 39968 /dev/mapper/RB_ASMDISK3
              SDG_0003 204800 39967 /dev/mapper/RB_ASMDISK4
              SDG_0004 204800 39969 /dev/mapper/RB_ASMDISK5
              SDG_0005 204800 39973 /dev/mapper/RB_ASMDISK6

              So I droped disk group then added disk group using same disk ,again. Oracle started rebalance and it solved...

              NAME TOTAL_MB FREE_MB PATH
              --------------- ---------- ---------- ----------------------------------------
              FRA_0000 204800 178232 /dev/mapper/B_ASMDISK8
              FRA_0001 204800 176319 /dev/mapper/RB_ASMDISK13
              SDG_0000 204800 39969 /dev/mapper/RB_ASMDISK1
              SDG_0001 204800 39977 /dev/mapper/RB_ASMDISK2
              SDG_0002 204800 39968 /dev/mapper/RB_ASMDISK3
              SDG_0003 204800 39967 /dev/mapper/RB_ASMDISK4
              SDG_0004 204800 39969 /dev/mapper/RB_ASMDISK5
              SDG_0005 204800 39973 /dev/mapper/RB_ASMDISK6

              Thanks for advice......