Network Storage Protocols Discussions

Help interpreting available space

Hi all,

Can pls help me interprete the available space?

n3300> aggr show_space -h
Aggregate 'aggr0'

    Total space    WAFL reserve    Snap reserve    Usable space       BSR NVLOG
         4138GB           413GB           186GB          3538GB             0KB

Space allocated to volumes in the aggregate

Volume                          Allocated            Used       Guarantee
vol0                                873GB           202GB          volume
vol2                                252GB           106GB          volume

Aggregate                       Allocated            Used           Avail
Total space                        1126GB           309GB          2615GB
Snap reserve                        186GB            40MB           186GB
WAFL reserve                        413GB            42MB           413GB

--------------

n3300> lun show
    /vol/vol0/qtvms1a/lun0        60g (64424509440)   (r/w, online, mapped)
    /vol/vol0/qtvms4a/lun0       180g (193273528320)  (r/w, online, mapped)
    /vol/vol0/qtvms5a/lun0        60g (64424509440)   (r/w, online, mapped)

---------------

n3300> df -h
Filesystem               total       used      avail capacity  Mounted on
/vol/vol0/               671GB      495GB      176GB      74%  /vol/vol0/
/vol/vol0/.snapshot        0KB     4324KB        0KB     ---%  /vol/vol0/.snapshot
/vol/vol2/               250GB      249GB      486MB     100%  /vol/vol2/
/vol/vol2/.snapshot        0MB        0MB        0MB     ---%  /vol/vol2/.snapshot

---------------

1. Aggr0 has total space of 3.5TB. Correct?

2. How much space is available in vol0? I think it should be around 600GB, but why the df -h command shows only around 176GB?

Thank you.

34 REPLIES 34

Re: Help interpreting available space

Well, some ideas

  • volume size != file system size. So you may have 873GB volume with only 671GB file system inside. Check with vol status -b
  • if lun reservation is enabled, LUN full size is accounted as used in df output but only physically written blocks are accounted in aggr show_space output. You apparently have 300GB of LUNs and something else on the same volume (almost 200GB), but LUNs are mostly empty

Re: Help interpreting available space

This is the lun status -b:

n3300> vol status -b
Volume              Block Size (bytes)  Vol Size (blocks)   FS Size (blocks)  
------              ------------------  ------------------  ----------------  
vol0                4096                176060424           176060424         
vol1                4096                471859200           471859200         
vol2                4096                65536000            65536000

Yes, lun reservation is enabled.

So, can I still create lun on vol0 for about 300GB? I'm not sure what "else" is 200GB.

Re: Help interpreting available space

Hi,

1. You have put LUNs in the same volume as the system files, vol0. It is NetApp best practice and industry standard to NOT mix vol0 with any LUNs or other way of serving

    data.

2. You could easily reclaim some space by turning snap reserve to 0 (zero) on your aggregate and having no snapshots at aggr. level. Unless you ever think you will overwrite your entire    

    aggregate there is no need for this space to be reserved. I d recommend turning snapshots off and having no snap reserve, but its your call. You might have the option to use it.

Regards,

Eric

Re: Help interpreting available space

He has volume of size 671G (as confirmed by vol status -b). How comes that aggr show_space shows that 873G are allocated for this volume? What consumes extra 202G? How is it related to either system volume or aggregate snap reserve?

Re: Help interpreting available space

Can you give us the "df -hr" output, which will show us the space used by the fractional reserve.

My guess is that the vol size shown by "df -h" + fractional reserve space  = volume allocation in "aggr show_space". Your "df -gA" will also show a used that will be less than total space allocated as shown in "aggr show_space". Why NetApp does it this way, I don't know

Re: Help interpreting available space

n3300> df -hr
Filesystem               total       used      avail   reserved  Mounted on
/vol/vol0/               671GB      590GB       81GB      199GB  /vol/vol0/
/vol/vol0/.snapshot        0KB     4324KB        0KB        0KB  /vol/vol0/.snapshot
/vol/vol1/              1800GB     1800GB        0GB        0GB  /vol/vol1/
/vol/vol1/.snapshot        0TB        0TB        0TB        0TB  /vol/vol1/.snapshot
/vol/vol2/               250GB      249GB      486MB        0MB  /vol/vol2/
/vol/vol2/.snapshot        0TB        0TB        0TB        0TB  /vol/vol2/.snapshot

n3300> df -gA
Aggregate                total       used      avail capacity 
aggr0                   3538GB      922GB     2615GB      26% 
aggr0/.snapshot          186GB        0GB      186GB       0% 
aggr1                   3538GB     1802GB     1736GB      51% 
aggr1/.snapshot          186GB       39GB      146GB      21%

Thanks for helping me. I'm really newbie here.

Re: Help interpreting available space

Hmm ... question: does NetApp reserve space immediately or only when snapshot is created? I remember having read something on this matter but forgot where.

If space is reserved immediately, df output makes sense. aggr show_space still not

OK, answering to myself. Quoting TR-3483: Data ONTAP removes or reserves this space from the volume as soon as the first Snapshot copy is created. There are some snapshots on vol0 (as indicated by snap reserve being != 0), which explains reservation.

Does not explain aggr show_space though

Message was edited by: aborzenkov

Re: Help interpreting available space

Nice, we found the missing 200 GB in the fractional reserve space. And yes, I also don't understand why NetApp did it this way

Assuming vol0 is the root volume, don't put LUNs in your root volume because it is not supported.

Re: Help interpreting available space

Ok, I've made mistake by using vol0 for LUN.

Can pls tell me the primary reason why I shouldn't do that?

Any remediation I can do about it? Maybe moving the LUN to other volume. Is it risky?

So, for this mistake, how much space I've wasted? Is it the 200GB?

Re: Help interpreting available space

My posting was pretty clear, I was providing a fix rather than trying to guess without info from the controller.

I ll explain for you if you want: If you have got no more disk for your volumes in your aggr. you can turn aggr. snap reserve off and get more space for your volumes.

I reckon you know this though.

Eric

Re: Help interpreting available space

Hi, it's me again. I think it's still related to this question.

Today, when I try to create a LUN on vol3, it errors:

n3300> igroup create -i -t vmware ig_sgvms12 iqn.1998-01.com.vmware:sgvms12
Mon Nov 23 10:01:24 GMT [lun.igroup.tmpFileWriteFailed:error]: Failed to write to the temporary igroup metafile (Initiator group change not stored on disk; unable to write new file).
igroup create: Initiator group change not stored on disk; unable to write new file

Mon Nov 23 10:50:00 GMT [wafl.vol.full:notice]: file system on volume vol0 is full

I've been reading Netapp forum and found 2 possible solutions:

1. Set Fractional Reserve to zero. But it's very risky because the LUN will go offline if space is out.

But, if I keep total LUN size to be lower than the Volume size, I should be safe, right?

2. Set snapshot off, but I have turned off snapshot on aggr0, haven't I?

Is there any workaround for this situation?

Is it by increasing the size of vol0?

Thank you.

This is related data:

n3300> aggr status
           Aggr State      Status            Options
          aggr1 online     raid4, aggr      
          aggr0 online     raid4, aggr       root, nosnap=on

n3300> df -hr
Filesystem               total       used      avail   reserved  Mounted on
/vol/vol0/               671GB      671GB        0MB      242GB  /vol/vol0/
/vol/vol0/.snapshot        0KB     4432KB        0KB        0KB  /vol/vol0/.snapshot
/vol/vol1/              1800GB     1800GB        0MB        0MB  /vol/vol1/
/vol/vol1/.snapshot        0MB        0MB        0MB        0MB  /vol/vol1/.snapshot
/vol/vol2/               250GB      249GB      471MB        0MB  /vol/vol2/
/vol/vol2/.snapshot        0MB        0MB        0MB        0MB  /vol/vol2/.snapshot
/vol/vol3/               500GB      499GB       17MB        0MB  /vol/vol3/
/vol/vol3/.snapshot        0MB        0MB        0MB        0MB  /vol/vol3/.snapshot

n3300> df -gA
Aggregate                total       used      avail capacity 
aggr0                   3538GB      922GB     2615GB      26% 
aggr0/.snapshot          186GB        0GB      186GB       0% 
aggr1                   3538GB     2302GB     1236GB      65% 
aggr1/.snapshot          186GB       10GB      175GB       6%

n3300> aggr show_space -h
Aggregate 'aggr0'

    Total space    WAFL reserve    Snap reserve    Usable space       BSR NVLOG
         4138GB           413GB           186GB          3538GB             0KB

Space allocated to volumes in the aggregate

Volume                          Allocated            Used       Guarantee
vol0                                922GB           250GB          volume
vol2                                252GB           107GB          volume

Aggregate                       Allocated            Used           Avail
Total space                        1174GB           358GB          2615GB
Snap reserve                        186GB            40MB           186GB
WAFL reserve                        413GB            56MB           413GB


Aggregate 'aggr1'

    Total space    WAFL reserve    Snap reserve    Usable space       BSR NVLOG
         4138GB           413GB           186GB          3538GB             0KB

Space allocated to volumes in the aggregate

Volume                          Allocated            Used       Guarantee
vol1                               1821GB          1519GB          volume
vol3                                500GB           712KB          volume

Aggregate                       Allocated            Used           Avail
Total space                        2321GB          1519GB          1236GB
Snap reserve                        186GB            10GB           175GB
WAFL reserve                        413GB           206MB           413GB

n3300> vol status vol0 -v
         Volume State      Status            Options                     
           vol0 online     raid4, flex       root, diskroot, nosnap=on,  
                                             nosnapdir=off, minra=off,
                                             no_atime_update=off, nvfail=off,
                                             ignore_inconsistent=off,
                                             snapmirrored=off,
                                             create_ucode=off,
                                             convert_ucode=off,
                                             maxdirsize=9175,
                                             schedsnapname=ordinal,
                                             fs_size_fixed=off,
                                             guarantee=volume, svo_enable=off,
                                             svo_checksum=off,
                                             svo_allow_rman=off,
                                             svo_reject_errors=off,
                                             no_i2p=off,
                                             fractional_reserve=100,
                                             extent=off,
                                             try_first=volume_grow
        Containing aggregate: 'aggr0'

                Plex /aggr0/plex0: online, normal, active
                    RAID group /aggr0/plex0/rg0: normal

Re: Help interpreting available space

Hi,

From what I am seeing your vol0 is full, its in a different aggregate than your vol3.

vol0 is typically system volume with the operating system in it, it should never get full.

are you using it to share data?

What I would do if I was you I would map c$ on the controller and free up space.

Go into /etc/crash, look for old core dumps and delete if you dont need them.

what does

cifs shares

exportfs

give? can you post it here?

Eric

Re: Help interpreting available space

Hi Eric,

This is the data:

n3300> cifs shares
Name         Mount Point                       Description
----         -----------                       -----------
ETC$         /etc                              Remote Administration
            ** priv access only **
HOME         /vol/vol0/home                    Default Share
            everyone / Full Control
C$           /                                 Remote Administration
            ** priv access only **

exportfs returns nothing. I haven't used it for NFS.

I think I have CIFS license, how do I set it up so that I can access it?

I use vol0 for LUN too.. which people say it's a mistake. I know. But, the total LUN size on vol0 is still below the volume size. It should be ok right?

Re: Help interpreting available space

Hi again,

Look at this:

n3300> df -gA
Aggregate                total       used      avail capacity 
aggr0                   3538GB      922GB     2615GB      26% 
aggr0/.snapshot          186GB        0GB      186GB       0%

You have reserved 186GB for aggr. snapshots but none are used. So you could free up 186GB of space in the aggr. but setting

aggr. snap reserve to 0%. please post here:

snap sched -A vol0

snap reserve -A vol0

Furthermore you seem to have enough space to increase the volume size

vol size vol0 750g    > choose your size.

Long term I recommend moving the LUN. You can now see the impact of ignoring best practice.

Eric

Re: Help interpreting available space

Thanks Eric for guiding me.

n3300> snap sched -A vol0
Aggregate vol0 does not exist or is not online.
n3300> snap reserve -A vol0
usage:
snap list [-A | -V] [-n] [-b] [-l] [[-q] [<vol-name>] | -o [<qtree-path>]]
snap create [-A | -V] <vol-name> <snapshot-name>
snap delete [-A | -V] <vol-name> <snapshot-name> |
snap delete [-A | -V] -a [-f] [-q] <vol-name>
snap delta [-A | -V] [<vol-name> [<snapshot-name>] [<snapshot-name>]]
snap rename [-A | -V] <vol-name> <old-snapshot-name> <new-snapshot-name>
snap sched [-A | -V] [<vol-name> [weeks [days [hours[@<list>]]]]]
snap reclaimable <vol-name> snapshot-name ...
snap reserve [-A | -V] [<vol-name> [percent]]
snap restore [-A | -V] [-f] [-t vol | file] [-s <snapshot-name>] [-r <restore-as-path>] <vol-name> | <restore-from-path>
snap autodelete <vol-name> [on | off | show | reset | help] |
snap autodelete <vol-name> <option> <value>...

So, to claim that 186GB, is this what I can do?

snap reserve vol0 0

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