RainbowShaggy

[DSM 6.1.2] Question about disk management in ESXi

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Hello,

 

I'd like to ask. I want to use DSM on ESXi, but I have a question about disks and RAID's. I don't have much capacity, so I'd like to expand size gradually depends on free space and I don't want to use mirroring and data protection for now, so I'm thinking about RAID 0, JBOD or Basic. My idea is, that I assign about 150-200 GB in the beginning and then I will expand the space about 50 GB in the future.

I tried expand the space in ESXi, but in DSM I saw that the disk is bigger, but I couldn't somehow expand the space on existing RAID group.

 

Could anyone help me, how can I solve this situation with expanding existing RAID groups?

 

Thanks

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I'm just doing my first trials with ESXi. I intend to physically pass through complete hard drives but SMART doesn't seem to work this way. But that's a different problem.

 

One idea would be not to enlarge the already existing drive (e.g. by 50 GB) but to add an additional disk (with 50 GB) later and use this additional drive for expanding the existing one using JBOD.

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Firstly, you must remember that unless you're passing the entire drive through to DSM to manage, you're effectively creating virtual disks with all the limited overheads created by ESXi.  Performance will effectively be less than normal as the virtual drive has to go through multiple layers before it finally hits the real drive.

 

With that out of the way however, your best option is as wer suggested to use single 'drives' with the maximum size you want per drive and then add them.  DSM won't likely recognise the increased size of the bigger drive as its already partitioned it and installed DSM on it.  You could create 2 x 100 GB virtual drives and JBOD them and then expand the array later by adding an additional 100 GB virtual drive.

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Thank you for your replies. The problem is, that I have small disks on my server and I want to manage these drives by ESXi for now because I'd like use this drives not only for DSM, but for other systems too. So, If I undrestand correctly. Even If I extend the space for the virtual disks in ESXi and the RAID group is already created in DSM, the change will not take effect. So your suggestions is create JBOD at the beginning for 100-200 GB and then expand it by adding next 50-100 GB virtual drives?

 

Thanks

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8 hours ago, Benoire said:

Firstly, you must remember that unless you're passing the entire drive through to DSM to manage, you're effectively creating virtual disks with all the limited overheads created by ESXi.  Performance will effectively be less than normal as the virtual drive has to go through multiple layers before it finally hits the real drive.


Interesting ... How do you pass through a drive to DSM on ESXi 6.5?

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tried something according to an howto ... but killed my server.

 

By changing the B120 Raid Controller to passthru in the hardware settings, you can't set this back.
Neither in the GUI nor in the esx.conf ... after reboot it's always on passthru ...

And I want passthru to a disk, not the whole controller

 

Anyway, setup will take a few minutes or up to an hour ... 
Back from the beginning ... it's weekend  

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its possible to pass only one disk? are you sure, i think you have to pass all controler.

the only way to pass disks independent is Raw Device Mapping, that way you chose disks individualy, but this is not passthrough.

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11 hours ago, hpk said:


Interesting ... How do you pass through a drive to DSM on ESXi 6.5?

There are two different ways, one is to use Raw Disk Mapping (RDM) within ESXi, but this requires your controller to allow this or the simple PCI passthrough using DirectIO if your motherboard supports it and you're ESXi datastore is not on the controller you're passing through.

 

RDM is an abstracted approach where by the disk is still managed by ESXi but the disk can only be used by the application you've passed it through to.  It has the same full speed access as directio but often won't pass the SMART data through.  RDM drives are added in a similar manner to virtual drives and you can make them appear in DSM in the order their loaded in to the machine.

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What do you have to do, before you're able to pass a disk through as RDM disk?
The option is not available, when I try to add a disk.

 

My setup:
- HP ProLiant MicroServer, Xeon, 16GB RAM 

- SSD Disk in Bay 1 for ESXI and Virtual Machines
- HDD Disk in Bay 2 as DataStore for Virtual Machines, except DS3617XS
- HDD Disk in Bay 3 as DataStore for DS3615xs

 

All three disks are on the same Controller, and I'd like to have best performance for the disk in Bay 3 (exclusive for XPEnology ...)

As mentioned, I don't have the option to add an RDM Disk. I guess, it needs some prerequisites to be able to pass the HDD in Bay 3 exclusively through to XPEnology.

 

Who can help? 

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Thank you, I'll read it carefully and try it out.

Currently, I'm doing a backup wich takes ages, the volume is really the limiting factor.
About 1GB per minute is really slow ...

 

XPEnology_Volume.thumb.JPG.879bca635934526c0b1d04522cb30a51.JPG

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Yesterday i passed my baremetal setup to esxi.
On esxi, just created one machine with the same loader as baremetal.
Added one virtual disc just to finish setup, same sn, same mac.
Pluged in one disc with 2tb from baremetal configured as rdm, boot machine and all dsm setud was exacly like on baremetal( only volume degraded because bm as 2 discs on raid 1).
All data, all package and setup was working as on bm.
Today im going to plugin the second disc to fix volume and raid inside dsm.

This was done on esxi6.

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I get the following error:

[root@localhost:/dev/disks] vmkfstools -r /vmfs/devices/disks/vml.0200020000600508b1001ce164482da257de5d2e8a4c4f47494341 bay3.vmdk -a lsilogic
Option --adaptertype is deprecated and hence will be ignored
Failed to create virtual disk: Unknown object error (6475)

 

Without the adaptertype option:

 

[root@localhost:/dev/disks] vmkfstools -r /vmfs/devices/disks/vml.0200020000600508b1001ce164482da257de5d2e8a4c4f47494341 bay3.vmdk
Failed to create virtual disk: Unknown object error (6475)

 

Any idea, what's going wrong?

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Was a syntax issue:

[root@localhost:~] vmkfstools -z /vmfs/devices/disks/vml.0200020000600508b1001ce164482da257de5d2e8a4c4f47494341 "/vmfs/volumes/Bay1 SSD DataStore/HPEsynology/bay3.vmdk"

 

this worked ... 

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and the performance has improved significantly, now, the limiting factor seems to be the 1Gbps Network ...
But I can live with that :-)

 

 

XPE_RDM.JPG

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There you go :-) Raw disk mapping is as close as you'll get to passthrough but DSM won't report on SMART errors as it can't read this data... You might have to create / find a script for esxi that can read the smart data.

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