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ReadyNAS 2120 V2 hangs alost every month and LUN connection problem
Hi , I have some problem with this hardware.
1.Sometimes my ESXi reboot, and LUNs are not able to reconnect. I see that, when I will try reboot NAS, I am warn that there are still active LUNs....
It seems that iSCSI is useless on this devices.
Since I had removed whole iSCSI configuration, my NAS become much more stable, even with snapshots and NFS datastore for ESXi.So my recomendation, Disable iSCSI.
You should investigate why your ESXi server is rebooting. You should always reboot it safely.
The RN2120 is a cost effective rackmount device designed for light use business cases.
How many LUNs do you have and how many VMs are they for?
Are you using thin or thick LUNs?
Are you using snapshots?
What about sync writes.
You should be using thick LUNs, with no snapshots and sync writes disabled.
You should also turn off VAAI in ESXi.
If the wrong settings were set you may need to backup your data, delete the LUN and create a fresh LUN.
Thank you for fast response.
I am loosing connection with hypervisor, the main reason is that it is on USB drive, and sometimes under high load it is happening.
But this is not the point here.
I am turning off all VMs, and forcely reboot server.
After that some LUNs are not reconnected.
VM use iscsi as storage(backup,data). OSes are only 4.
Currently I have 3 LUNs
All are THIN, I use snapshots (daily),sync writes ON, VAAI ON.
So basically it is oposite to what you wrote :)
Is there any reason why I should not use VAAI,snapshots,thin,and daily snapshots?
Using thin LUNs will impact performance as the LUN has to be grown over time and may become fragemneted. For ESXi you want to configure things to optimise performance and thick LUNs are the way to go.
Snapshots use CoW at the point in time they are taken. With something that has a huge level of writes to it in place you're going to get a lot of fragmentation. A VM is a classic example of this.
Likewise bit-rot protection should be disabled (we link this to enabling/disabling) CoW.CoW (Copy on Write) means that when changes are made the existing data is not overwritten, but instead written to free space. So you will get a huge level of fragmentation using it with VMs.
CoW is enabled per LUN/share, and the way to undo it would be to backup your data, delete the LUN, create a LUN with CoW disabled and restore your data from backup.Sync writes are good for verifying writes are synced properly, but this does impact performance which is a problem for VMs. With VMs you want to configure things to optimise performance.
We don't support VAAI and we mention that in this article. Trying to use a feature that is not supported is going to lead to issues.
Ok, some of your points makes sense.
But this is not answer on my question.
How can I list active LUNs and disconnect some of them?
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