In this 3PAR 101 series so far we have looked at 3PAR fundamentals and the systems unique approach to RAID, in Part 2 we looked into Common Provisioning Groups (CPGs) Now we get onto the stage where we can provision some storage to hosts by using virtual volumes and vluns!
Virtual volumes (VV’s) are HPE’s terminology for what would most commonly be called a LUN, a LUN which has been presented or exported to a host is called a VLUN. Virtual volumes draw their space from CPG’s and come in two varieties Fully Provisioned Virtual Volumes (FPVV) and Thin Provisioned VV (TPVV). A FPVV uses all the allocated space upfront, so if a 100GB VV is created straight away 100GB of space will be used from the CPG. With a TPVV only the space that is demanded is used, so if a 100GB VV is created and only 50GB of that space is used only 50GB of space will be demanded from the CPG.
A thin provisioning licence is required to use TPVV and assuming this is in place TPVV are the default type of VV created. Today if you purchase a system you get the full licence bundle included and so this becomes less of a concern.
Another type of Virtual Volume was introduced with the 3PAR all flash systems. The Thin Deduplicated Virtual Volume (TDVV) as the name suggested this was a volume that was both deduped and thin provioned. 3PAR OS 3.3.1 depreciated the TDVV volume type and made dedupe a property of a volume that could just be turned on. 3.3.1 also introduced the capability to enable compression on volumes.
Creating a VV and VLUN SSMC
Enough theory let’s get on and create a VV, first in the 3PAR SSMC:
1 Open SSMC and from the main menu select Virtual Volumes
2 Click the green Create Virtual Volume button on the top left of the screen
3 What appears next is the simple Virtual Volume creation screen. The only information you have to supply is:
- Name – the name you wish to call the Virtual Volume
- System – If you are connected to more than one system, chose the system you want to create the volume on
- Size – How large the volume needs to be
Further fields you can change if you wish:
- Provisioning – choose from thick or thin provisioning
- CPG – Select a different CPG for storing the virtual volume in
4 If you want to create an additional volume you are done. But if you need to set any of the following, choose Edit additional settings
- Copy CPG – The CPG you want metadata and snapshots to be stored in
- Number of volumes – if you want to create multiple volumes at the same time
- Volume sets – Add the volume to a volume set
- Comments – Add any comments you wish
5 Next we present the newly created volume to a host. Still in the create virtual volume wizard select add
In the box that appears choose to export the volume to a host as below, or select to export it to a group of hosts using a host set.
To enable dedupe and compression on the volume follow the 3PAR Dedupe + Compression Deep Dive
Creating a VV – CLI
This section looks at how we create a volume and then export it to a host using the command line.
createvv -tpvv -pol zero_detect NL_R6 VirtualVolume2 100G
Lets break down the CLI options a little
- createvv – core command
- -tpvv make thin provisioned volume
- -pol zero_detect scan for zeros on incoming writes
- CPG name – in my case NL_R6
- VV name – in my case VirtualVolume2
- Size of volume – in my case 100GB
Creating a Vlun – CLI
createvlun VirtualVolume2 auto host1
- createvlun – core command
- VV name – in my case VirtualVolume2
- Lun ID – auto in this case
- Hostname – host1
If you only use the new management tools for 3PAR that it your done, fineto. This blog has over 150+ 3PAR articles check out a selection of them here. If you missed any of the 3PAR 101 series catch up on them:
3PAR 101 – Part 3 – Virtual Volumes and Vlun’s
Creating a VV – 3par management Console
If you still use the 3PAR management console then read on:
1 In the management pane select Provisioning and then from the common actions pane select Create Virtual Volume
2 Next you will see a welcome screen which has a lot of useful info on creating VV’s, if you do not want to see this again click the skip this step tick box and click next
3 The basic information you will need to complete when creating a VV is highlighted in the screenshot below. Thin provisioned will be selected by default, enter the name and size and then the CPG you want the VV to sit in. Remember the CPG you choose will determine the performance and availability level of the volume. The copy CPG will only be needed if you use snapshots
4 The screenshot below shows what you will see if you tick the advanced options checkbox. Generally you can leave all this to deafult and will not need to select advanced options
5 The final screen shows a summary of the sections you have made, if you are happy just click finish here
Creating a Vlun – 3par management console
Next we need to export (provision) the virtual volume to the host
1 In the management pane select Provisioning and then from the common actions pane select Export Volume
2 Next you will see a welcome screen which has a lot of useful info on creating VLUN’s, if you do not want to see this again click the skip this step tick box and click next
3 On the left hand side of the screen you need to select the name of the volume to export, on the right hand side you need to choose the host to export to. By ticking auto for export with LUN values it will automatically choose the LUN ID for you. When your happy with your selection click next
4 The final screen shows a summary of the sections you have made, if you are happy just click finish here
If you have missed it, check out parts One (3PAR architecture) and Two (CPG’s) of this 3PAR beginner guide series.
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