Expand existing disk group and add new dg

[luckiblueee]

I want to add two new flash disks to my existing all flash groups on all 9 hosts. On every single host there is one disk group and there is lots of VMs working on it.

My first question is: Can I expand existing disk group without downtime (on the fly) just by adding two new disks?

Second question is: Can I create new disk group (same size, type and quantity of disks as first one) on every host without consequences for currently existing dg on the host?

Is there anything I need to know about extending and creating new disk groups?

Thanks in advance.

[TheBobkin · Accepted solution]

Hello luckiblueee,

Welcome to vSAN Communities, I hope you find some good info on this forum and please feel free to ask anything that has not been addressed.

Q1: Yes, you can add available capacity SSDs to an existing disk-group at any time without down-time.

Up to a maximum of 7 capacity drives can be in each DG.

Q2: Creating a new Disk-group has no impact on existing DGs, though if they are sharing the same controller the throughput resources of this will be shared between the DGs.

It is advised to always aim to keep DGs homogenous (in hardware and capacity), this matters more with smaller clusters though and node to node equal space is a good compromise if identical DGs are not feasible.

Q3: Not much to it, just need blank disks and either the Web Client or CLI:

docs.vmware.com/en/VMware-vSphere/5.5/com.vmware.vsphere.storage.doc/GUID-666D9839-2726-4936-8C0F-94476ECE0606.html

pubs.vmware.com/vsphere-6-5/index.jsp?topic=%2Fcom.vmware.vcli.examples.doc%2FGUID-01749B4C-7BD0-43FA-9083-B2DEC48F2794.html

pubs.vmware.com/vsphere-6-0/index.jsp?topic=%2Fcom.vmware.vcli.ref.doc%2Fesxcli_vsan.html

Bob

[luckiblue1920]

TheBobkin​ how long it takes to extend disk group or create new one? Let's say we have 5 disks with size of 750GB each one (flash) and vSAN version is 6.6. We want to add 2 new disks. Is it depends on amount of data on currently used disks?

[TheBobkin]

Hello,

Adding disks takes a matter of seconds not minutes.

Not really noticed any correlation between size/brand and time taken as this is a fast process.

Bob