Testing oVirt...
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@emad-r said in Testing oVirt...:
Let us talk about Gluster, how do you feel safe with it ?
saw you choose an option with RAID 6, i dont get that cause from my trial, I make RAID and group disks then create Gluster volume from those mdraid volume, but it seems you did RAID 6 afterwards, hmm whats the logic behind that ?
What type of Gluster volume are you using, just distributed ?
I m still learning HCI so thus the beginner vibe
No RAID6, I'm using RAID10.
Gluster volume is Replicate + Arbiter
This is a good blog post to get you started: https://www.ovirt.org/blog/2018/02/up-and-running-with-ovirt-4-2-and-gluster-storage/
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@dustinb3403 said in Testing oVirt...:
@dafyre said in Testing oVirt...:
Can we use the oVirt system to manage an existing KVM server?
( I want to try oVirt, but really don't want to wipe out the system I currently have set up )I tried setting up oVirt a few versions ago and from what I could find, it's almost expected you have a minimum of 3 physical hosts for it.
So no, you won't be able to manage a standalone KVM server since everything has to get built to be managed by the oVirt Engine.
You can now do a single host w Gluster:
https://www.ovirt.org/documentation/gluster-hyperconverged/chap-Single_node_hyperconverged/Here's a screenshot of my single node install:
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@emad-r said in Testing oVirt...:
Let us talk about Gluster, how do you feel safe with it ?
Not sure, since I'm new to the whole Gluster concept.
saw you choose an option with RAID 6, i dont get that cause from my trial, I make RAID and group disks then create Gluster volume from those mdraid volume, but it seems you did RAID 6 afterwards, hmm whats the logic behind that ?
Hardware RAID is recommended instead of MDADM.
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@fateknollogee Hardware RAID is recommended because a lot of people lack the practice and skill with software RAID to appropriately maintain/troubleshoot/fix software raid.
Plus you often get features like Blind swap.
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@dustinb3403 said in Testing oVirt...:
@fateknollogee Hardware RAID is recommended because a lot of people lack the practice and skill with software RAID to appropriately maintain/troubleshoot/fix software raid.
Plus you often get features like Blind swap.
Nope...
The folks at RH say, currently, performance is better with HW RAID & that is how most of their testing/validation is done. -
@fateknollogee said in Testing oVirt...:
@dustinb3403 said in Testing oVirt...:
@fateknollogee Hardware RAID is recommended because a lot of people lack the practice and skill with software RAID to appropriately maintain/troubleshoot/fix software raid.
Plus you often get features like Blind swap.
Nope...
The folks at RH say, currently, performance is better with HW RAID & that is how most of their testing/validation is done.That's odd, but okay. I would generally think they make the recommendation because they know there is a huge lack of understanding on how software raid needs to be managed.
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@emad-r said in Testing oVirt...:
Let us talk about Gluster, how do you feel safe with it ?
I'm guessing you really don't know much about Gluster and it's history?
https://en.m.wikipedia.org/wiki/GlusterThink of it like RAID, but spread over a network instead of locally. It's been around since 2005, and is used by some very large cloud providers today.
So I feel totally safe with it, and actually deployed it once. Great platform when it's needed, and a complete waste of time when it's not.
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@travisdh1 said in Testing oVirt...:
@emad-r said in Testing oVirt...:
Let us talk about Gluster, how do you feel safe with it ?
I'm guessing you really don't know much about Gluster and it's history?
https://en.m.wikipedia.org/wiki/GlusterThink of it like RAID, but spread over a network instead of locally. It's been around since 2005, and is used by some very large cloud providers today.
So I feel totally safe with it, and actually deployed it once. Great platform when it's needed, and a complete waste of time when it's not.
That and Gluster is not a replacement for good backups.
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@dustinb3403 said in Testing oVirt...:
@fateknollogee said in Testing oVirt...:
@dustinb3403 said in Testing oVirt...:
@fateknollogee Hardware RAID is recommended because a lot of people lack the practice and skill with software RAID to appropriately maintain/troubleshoot/fix software raid.
Plus you often get features like Blind swap.
Nope...
The folks at RH say, currently, performance is better with HW RAID & that is how most of their testing/validation is done.That's odd, but okay. I would generally think they make the recommendation because they know there is a huge lack of understanding on how software raid needs to be managed.
I'm also guessing it's because RAID isn't necessarily needed. The overhead for software RAID doesn't gain much if you're bricks are replicated anyway.
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3 + 1 node hyperconverged: Volume layout
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3 + 1 node hyperconverged: brick layout
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@emad-r said in Testing oVirt...:
Let us talk about Gluster, how do you feel safe with it ?
It's the industry standard RAIN system.
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@travisdh1 said in Testing oVirt...:
Think of it like RAID, but spread over a network instead of locally. It's been around since 2005, and is used by some very large cloud providers today.
Not quite. Gluster is RAIN, not Network RAID. You are describing DRBD.
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@stacksofplates said in Testing oVirt...:
@dustinb3403 said in Testing oVirt...:
@fateknollogee said in Testing oVirt...:
@dustinb3403 said in Testing oVirt...:
@fateknollogee Hardware RAID is recommended because a lot of people lack the practice and skill with software RAID to appropriately maintain/troubleshoot/fix software raid.
Plus you often get features like Blind swap.
Nope...
The folks at RH say, currently, performance is better with HW RAID & that is how most of their testing/validation is done.That's odd, but okay. I would generally think they make the recommendation because they know there is a huge lack of understanding on how software raid needs to be managed.
I'm also guessing it's because RAID isn't necessarily needed. The overhead for software RAID doesn't gain much if you're bricks are replicated anyway.
But the overhead of hardware RAID wouldn't gain anything, either.
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oVirt Node is installed on a 64gb SATADOM
Gluster is on a 2TB RAID array.Here is the disk layout:
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@scottalanmiller said in Testing oVirt...:
@fateknollogee said in Testing oVirt...:
Hardware RAID is recommended instead of MDADM.
By whom?
By the oVirt devs.
You can go & look for RHs best practice for RHEV, it also says use HW RAID. -
@scottalanmiller said in Testing oVirt...:
@stacksofplates said in Testing oVirt...:
@dustinb3403 said in Testing oVirt...:
@fateknollogee said in Testing oVirt...:
@dustinb3403 said in Testing oVirt...:
@fateknollogee Hardware RAID is recommended because a lot of people lack the practice and skill with software RAID to appropriately maintain/troubleshoot/fix software raid.
Plus you often get features like Blind swap.
Nope...
The folks at RH say, currently, performance is better with HW RAID & that is how most of their testing/validation is done.That's odd, but okay. I would generally think they make the recommendation because they know there is a huge lack of understanding on how software raid needs to be managed.
I'm also guessing it's because RAID isn't necessarily needed. The overhead for software RAID doesn't gain much if you're bricks are replicated anyway.
But the overhead of hardware RAID wouldn't gain anything, either.
It doesn't pull anything from the OS though. SW would actually use resources the system could use. So the only thing you would see is less capacity.
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@stacksofplates said in Testing oVirt...:
@scottalanmiller said in Testing oVirt...:
@stacksofplates said in Testing oVirt...:
@dustinb3403 said in Testing oVirt...:
@fateknollogee said in Testing oVirt...:
@dustinb3403 said in Testing oVirt...:
@fateknollogee Hardware RAID is recommended because a lot of people lack the practice and skill with software RAID to appropriately maintain/troubleshoot/fix software raid.
Plus you often get features like Blind swap.
Nope...
The folks at RH say, currently, performance is better with HW RAID & that is how most of their testing/validation is done.That's odd, but okay. I would generally think they make the recommendation because they know there is a huge lack of understanding on how software raid needs to be managed.
I'm also guessing it's because RAID isn't necessarily needed. The overhead for software RAID doesn't gain much if you're bricks are replicated anyway.
But the overhead of hardware RAID wouldn't gain anything, either.
It doesn't pull anything from the OS though. SW would actually use resources the system could use. So the only thing you would see is less capacity.
Sort of, but the CPU overhead of software RAID is nominal, but as it is faster than hardware RAID and storage is the common bottleneck, it normally makes the system faster rather than slower.
So in CPU terms, there is a small overhead to software RAID that you normally can't notice. But to the overall system, there is normally a negative overhead, meaning you get more out of your server, rather than less.
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@fateknollogee said in Testing oVirt...:
@scottalanmiller said in Testing oVirt...:
@fateknollogee said in Testing oVirt...:
Hardware RAID is recommended instead of MDADM.
By whom?
By the oVirt devs.
You can go & look for RHs best practice for RHEV, it also says use HW RAID.I don't trust any recommendation that doesn't include the logic as to why. Likely their logic is "because most of our users don't know how to do MD and we don't want to be asked questions" or "we are sponsored by server vendors" or "our users always have hardware RAID already and it can't easily be disabled and they get confused" or "we think it's what people want to hear."
FreeNAS recommends software RAID, but if you dig into "why" it's based on selling more support and has nothing to do with what is good for the customer.
