Article ID: 117634, created on Oct 1, 2013, last review on Jun 17, 2016

  • Applies to:
  • Virtuozzo


This video provides an overview of tools available for managing Parallels Cloud Storage cluster and tunable cluster parameters.

This video is the part of Parallels Cloud Storage course:





Tool to manage any cluster parameters from any machine in the cluster


Tool to mount Cloud Storage on client machines


Tool to collect logs and auxiliary information for support


Tool to validate storage for reliability and data consistency in case of power outage

Configuring Cluster Parameters

Redundancy Parameters

  • Default replicas (replicas=default:min)

    • Increase to have higher redundancy level
    • Decrease to save disk space
  • Min replicas (replicas=default:min)

    • Increase to have faster recovery process and minimize the risk of service interruption
    • Decrease to save storage traffic
  • Set on per-directory basis:

    ~# pstorage -c clustername1 set-attr -R /pstorage/clustername1 replicas=3:2
    ~# pstorage -c clustername1 set-attr -R /pstorage/clustername1/private/100 replicas=5:3

Performance Parameters

  • Client SSD cache (client-ssd-cache=0|1)

    Enables (1) or disables (0) SSD caching of data on a client

  • Tier (tier=0..3)

    Use to classify data storage by its speed

  • Set on per-directory basis:

    ~# pstorage -c clustername1 set-attr -R /pstorage/clustername1/private/100 client-ssd-cache=0 tier=1
    ~# pstorage -c clustername1 set-attr -R /pstorage/clustername1/private/200 client-ssd-cache=1 tier=0

High Performance

SSD Write Journaling on Chunk Server

  • When deploying Chunk Server role specify SSD drive for journaling data:

    ~# pstorage -c clustername1 make-cs -r /pstorage/clustername1-cs -j /ssd/clustername1/cs1 -s 30720
  • Leave 1/1000 of storage space on SSD drive for checksums

  • To choose performance in favour of reliability:

    • Configure data scrubbing (set to a smaller value)

      ~# pstorage -c clustername1 set-config mds.wd.verify_chunks=3
    • Disable data checksumming

      ~# pstorage -c clustername1 make-cs -r /pstorage/clustername1-cs -j/ssd/clustername1/cs1 -s 30720 -S

SSD Read Caching on Client

  • Mount storage with data cache parameter:

    ~# pstorage -c clustername1 /pstorage/clustername1 -C /ssd/clustername1/cache-directory -R 64000
  • Disable checksumming in favor to performance:

    ~# pstorage -c clustername1 /pstorage/clustername1 -C /ssd/clustername1/cache-directory -R 64000 -S
  • Do not forget to enable automatic mounting Cloud Storage in your /etc/fstab file:

    pstorage://clustername1 /pstorage/clustername1 fuse.pstorage cache=/ssd/clustername1/cache-directory,cachesize=64000,cachechksum=n 0 0

Additional Information

Documentation Portal

Official product page

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