Hi,

I did the above changes on the server ( adding enterprise disks for storage domains ),  and there are improvements. But.

I just had a vm getting into "VM paused due to I/O error"  :(  . 

This vm has both disks as "thin-provisioning", and it runs as an OpenShift node ( Centos 7).

Any chance that the problem could be because the disks are not "pre-alocated" and the filesystem writes are to intensive ?

Getting a bit worried since this stack it's supposed to be seen as a production system....

Thank you very much !

On Mon, Jul 16, 2018 at 3:59 PM, Andrei Verovski <andreil1@starlett.lv> wrote:

Hi,

Looks almost good, see comments below.

On 16 Jul 2018, at 13:48, Leo David <leoalex@gmail.com> wrote:

Thank you very much,  really helpfull.

So I will have:

2 x Sandisk ssd plus 240GB ( still consumer grade ) for OS

Run continues (2+ hours, random + sequential read/write) iozone tests (in a loop) before launching system on these SSD RAID.

You may be lucky or may be not.

2 x Samsung sm863a ( dc grade ) 1.9TB for creating 1 x raid1 ssd volume

4 x Dell 2.4TB spinning ( dc grade ) for creating 1 x raid10 spinning volume

1 x nvme car for quick / non critical fast volume

- I would go for gluster since there are chances to extend the cluster in near future.

You can also set shared volume on (at least) 2 x external SAN, NAS, NFS server, whatever.

Any thoughts on this config ?

Any thougts on configuring the perc controller to be gluster optimized ( for replicated / ditributed replicated volumes ) ?

Don’t think there are gluster-optimized settings.

Run iozone tests to find optimal settings depending on your workload.

Again,  thank you very much !

On Mon, Jul 16, 2018 at 1:11 PM, Andrei Verovski <andreil1@starlett.lv> wrote:

Hi, Leo,

I would recommend the following configuration:
RAID1 120GB for the OS and oVirt software
RAID10 (GB whatever you need) for VM data
I tested RAID5 it appears slower then RAID10.

Please note consumer SSD may appear to work with SAS RAID controller yet actually they DO NOT !
Load them with IOZONE stress test, and you will see complete freeze, and in case of OS install on these SSD, unbootable dead system.

I tested consumer WD and KingFast SATA SSD, with both HP and 3Ware/Broadcom SAS RAID cards, all of them failed IOZONE stress test.
BTW, you can buy 120GB used SAS server disks on ebay for something close to nothing.
Conventional (mechanical) SATA hard drives work fine with SAS RAID cards (at least in my case).

For single server you don’t need glusterfs, nfs is enough.

> On 16 Jul 2018, at 09:27, Leo David <leoalex@gmail.com> wrote:
>
> Hello everyone,
> Based on your experiance or well know best practices can you provide me with an advice on raid configuration ?
> I have a single server, that will have a couple of brand new enterprise grade ssds, spinning and one pci nvme card.
> The server ( Dell PE r630 ) comes wirt Perc h730p raid controller with 2gb cache.
> I am thinking of creating a raid 1 array with the 2 of ssd's and ne raid10 array woth the rest of for spinning hdds. Then different gluster volume on each,  to provide me 2 ( ssd / sata )  storage domains.
> What do you think on haveing raid1 / raid10 as underlying HA storage for gluster volumes ?
> At the moment a have some consumer devices ( samsung evo & seagate spinning shingled type ) and about every day the vms get into "VM has been paused due to storage IO errors" - i am thinking because of bad type hdds.
> Any thoughts on these ?
> Thank you ,
>
> Leo
> --
> Best regards, Leo David

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--

Best regards, Leo David

--

Best regards, Leo David

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