Host Storage

Host Storage requirements#

• Every host requires a disk of at least 10GB for OS installation
  • SSD recommended
• Storage hosts require additional disks
  • at least one extra disk
  • at least 100GB
  • SSDs and HDDs supported

Cluster requirements#

• Clusters require at least 3 storage hosts
  • storage hosts can run VMs as well as provide storage
  • minimum 3 storage hosts are required
  • 3+ storage hosts can provide triple-replication
  • 7 + hosts can provide Erasure Coding

Host configuration#

• SSDs are recommended for performance reasons
• Datastores should be created from sets of similar disks for performance uniformity
• FC or iSCSI LUNs can be used if required
• Any unused disks or LUNs should be removed from the system prior to installation
  • all present disks will be wiped
    • all disks except the boot disk will be used for a default datastore
    • if you have a mix of HDD and SSD we recommend detaching HDD disks during the install
  • remove/detach disks you want to retain
    • detach disks you want to use for additional datastores
    • re-attach disks for additional datastores after installation

Workload Tuning#

VM Squared is engineered to provide optimal backend storage performance. Depending on your workload you may wish to tune VM storage access.

This can be done by optimizing the VM HBA or matching the IO block size to your workload. sds infrastructure is tuned by the product but you have tunables at the workload level - virtIO queues, block size.

Disk Cache types can also be tuned on VM disks to match customer requirements.

Appendices#

Hardware RAID controllers#

Some RAID controller allow a JBOD setting, this will provide the best performance and hardware visibility.

For hosts with onboard RAID controllers that do not support JBOD, we recommend mapping each local disk directly to a RAID0 virtual disk.

To make these disks accessible to VM Squared:

• Create multiple RAID0 Virtual Volumes through the controller
• each volume dedicated to a single disk

Storage arrays#

For use cases when a RAID controller does not support passthrough you should utilize RAID0 single-drive volumes.

In this example we have a Dell PowerEdge VRTX with chassis-based shared PERC8 Controller. This example of a system with RAID grouping and LUN mapping is analogous to FC and iSCSI shared storage systems.

To make these disks accessible to VM Squared:

• Create multiple RAID0 Virtual Volumes through the controller
  • other systems may have RAID10 instead of RAID0
• each volume dedicated to a single physical disk
  • as many virtual volumes as you have disks
• each volume allocated to specific host within the chassis
  • FC/iSCSI systems must zone/mask each volume to a single host

Six RAID0 volumes have been generated, with three volumes designated for each individual host.

Every host is allocated exclusive access to three disks, thereby appearing as dedicated storage devices within VM Squared.