5 Replies Latest reply: Nov 7, 2012 5:53 AM by Balazs Papp RSS

    asm diskgroup really full?

    Me_101
      Hi gurus,

      after install RAC (11.2.0.3 two nodes) on linux, a warning appears shown a diskgroup almost full:
      SQL>  select group_number,  name, block_size, state, total_mb, free_mb, hot_used_mb from V$ASM_DISKGROUP WHERE NAME='VOL';
      
      
      GROUP_NUMBER NAME                           BLOCK_SIZE STATE         TOTAL_MB      FREE_MB HOT_USED_MB
      ------------ ------------------------------ ---------- ----------- ----------   ---------- -----------
                 4 VOL                          4096 MOUNTED          23838       284           0
      correctly, It's looks like almost full.

      It is a new RAC database, if i check any file at asmcmd:
      asmcmd> cd VOL
      asmcmd> ls
      asmcmd>
      no files appear, so i go to asmca and check:
      ASM CLUSTER FILE SYSTEM
      
      ACTIVE MOUNT POINT | STATE | ALL_MOUNT_POINTS | VOLUME DEVICE    | SIZE (GB) | VOLUME | DISK_GROUP | USED (%)
      /backup                 MOUNTED   /backup           /dev/asm/vol-24   22.91      VOL VOL       4.19
      it's only 4.19% in use

      what is happening? at filesystem is no files and have enough space, but asm shows that it is almost full
        • 1. Re: asm diskgroup really full?
          Balazs Papp
          ASM and ACFS are related (an ACFS volume is part of an ASM diskgroup), but not the same

          you have ASM diskgroup with 23 GB storage
          you created an ACFS volume on it with ~23 GB size

          from ASM point of view, the diskgroup is almost full, because of the ACFS volume
          from ACFS point of view, its empty, because you didnt put anything yet on that volume

          its similar as LVM
          you create a volume group (ASM diskgroup in this analogy) with 23 GB size
          then you create a volume (ACFS volume in this analogy) with nearly 23 GB size
          volume group is almost "full", while volume is empty
          • 2. Re: asm diskgroup really full?
            Me_101
            So this is not a problem? while ACFS shows that is not full, database can insert files there. ASM will show that it is almost full always. right?
            exist any way that syncronice ASM with ACFS?
            • 3. Re: asm diskgroup really full?
              Balazs Papp
              not a problem, its normal

              however storing database files on an ACFS volume is just 1 more unneeded layer, ASM alone is perfectly enough for this purpose
              exist any way that syncronice ASM with ACFS?
              what do you mean? space usage report?
              you dont synchonize them, as i already said, ACFS is part of ASM
              lets say your ASM is 23 GB
              then you could create for example and 5 GB, an 7 GB and a 9 GB volume and still store 2 GB on the diskgroup
              now how do you "synchronize" this?
              • 4. Re: asm diskgroup really full?
                Me_101
                ok, thanks alot. I got it.

                I means that when you check the space of the diskgroups, instead the warning of "diskgroup is almost full" shows the real space in ACFS.
                I.E., if you create an ACFS of 10G and has only 1Gb of space occuped, when you check the diskgroup space its looks like 1Gb, not the 10G.
                • 5. Re: asm diskgroup really full?
                  Balazs Papp
                  I.E., if you create an ACFS of 10G and has only 1Gb of space occuped, when you check the diskgroup space its looks like 1Gb, not the 10G.
                  no, if you create a 10G ACFS volume, ASM will always show that as 10G occupied, even if the ACFS volume is absolutely empty