VZ6 - PStorage - what happens when FULL?

Discussion in 'General Questions' started by futureweb, Feb 27, 2017.

  1. futureweb

    futureweb Tera Poster

    Messages:
    394
    Hey there,

    as I just tune our Storage Monitoring - some Questions came up - what happens if PSTORAGE is getting FULL?
    Let's say we have License of 10TB - and I reach 10TB ... will Pstorage deny writes? Or will it suspend CTs? Is there a Grace Periode? If writes are denied - does this happen when actually 10TB are used or earlier?
    Or do I have to fear ploop corruption? (or DB crashes within CTs as if storage is running out on real Servers...?!)

    thx 4 info
    Andreas Schnederle-Wagner
     
  2. Pavel

    Pavel A.I. Auto-Responder Staff Member

    Messages:
    475
    Hello,

    Strictly speaking pstorage itself will never suspend anything :) It's simply not-VZ aware enough to do so, it does not command anything to virtuozzo services.
    Containers will probably get -ENOSPACE on writes in such scenario. VMs have a different disk driver, they'll get PAUSED.

    As for the grace period - there is one:
    Code:
    [root@pcs-3rdline-7 ~]# pstorage -c 3rdline view-license | grep grace
            graceperiod=259200
            gracecapacity=5
    
    Where gracecapacity is
    You can see that in >documentation<.

    As for the DB - I'm not quite sure how will it behave. Probably depends on a DB solution itself, as in "how would it handle -ENOSPACE".
     
  3. futureweb

    futureweb Tera Poster

    Messages:
    394
    alright - thx for info!
    What would be if physical diskspace is actually running out? So no grace is possible? Will it fill up to 100% or does it have some safety margin - and will deny writes (ENOSPACE) at some certain %? (Some of our HPE SANs will stop all writes when 95%-98% full ...)
    thx
     
  4. Pavel

    Pavel A.I. Auto-Responder Staff Member

    Messages:
    475
    There is a safety margin within pstorage itself - we've discussed this previously if I recall.

    [root@pcs-3rdline-7 ~]# pstorage -c 3rdline get-config | grep fill_margin
    mds.alloc.fill_margin=5

    that is 5% of course
     
  5. futureweb

    futureweb Tera Poster

    Messages:
    394
    thx! ;-)
    Now that you say it - it sounds somehow familiar - but wasn't sure ...
     

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