I don't really get the point of SAN snapshots
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@scottalanmiller said in I don't really get the point of SAN snapshots:
@dave247 said in I don't really get the point of SAN snapshots:
I get what you mean now about a single storage controller unit not being redundant. And in our case, ours is not as we only have the one. You probably know this by now about my setup, that we have the "inverted pyramid of doom" going on.
Essentially anyone with a SAN has one. Not exactly guaranteed, but almost. It's the key reason SANs are deployed.
Many enterprises knowingly run IPODs because at huge scale, they can be cheap. And while IPODs cannot be as fast or as reliable as alternatives, enterprises also know that performance and reliability are not the end all, be all and that "cheaper" and "fast enough" and "safe enough" can be the right choice.
SMBs tend to copy this, but forget that enterprises make the decision based on scale, and assuming that there must be value, just project that the idea must be fast and reliable. So with the lack of scale, they end up spending a fortune to make their system not work as well. So there are good reasons that it all exists, but they don't apply well to the SMB market.
What was IPOD again? I remember you mentioning that in the video but I thought you were making some analogy to Apple iPods, but now I'm wondering if that's not the case. I did listen to most of the video but it was a very distracting morning with lots of interruptions.
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@dave247 said in I don't really get the point of SAN snapshots:
What was IPOD again?
Inverted Pyramid of Doom
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@DustinB3403 said in I don't really get the point of SAN snapshots:
@dave247 said in I don't really get the point of SAN snapshots:
What was IPOD again?
Inverted Pyramid of Doom
ooooh yes ok. FFS.
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An IPOD means you have 2 or more hypervisors with 1-2 switches with a SAN providing storage to your hypervisors.
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ok so lets say I didn't have a SAN and I didn't want to use vSAN or whatever. Is there another good method, such as maybe having two physical Windows servers basically serving up mirrored storage via iSCSI or FCoE?
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@DustinB3403 said in I don't really get the point of SAN snapshots:
An IPOD means you have 2 or more hypervisors with 1-2 switches with a SAN providing storage to your hypervisors.
yes I fully get the IPOD thing. I used to be a SpiceSquirts user and endured the many tedious posts of SAM.
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@dave247 said in I don't really get the point of SAN snapshots:
ok so lets say I didn't have a SAN and I didn't want to use vSAN or whatever. Is there another good method, such as maybe having two physical Windows servers basically serving up mirrored storage via iSCSI or FCoE?
You literally just described vSAN. Two servers mirrored up over either iSCSI or FCoE is vSAN. That's what makes it vSAN.
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Anything that talks over iSCSI or FCoE (or any other block protocol) is SAN. If you virtualize it, it's vSAN.
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@scottalanmiller said in I don't really get the point of SAN snapshots:
@dave247 said in I don't really get the point of SAN snapshots:
ok so lets say I didn't have a SAN and I didn't want to use vSAN or whatever. Is there another good method, such as maybe having two physical Windows servers basically serving up mirrored storage via iSCSI or FCoE?
You literally just described vSAN. Two servers mirrored up over either iSCSI or FCoE is vSAN. That's what makes it vSAN.
ooh ok I was thinking VSAN was a product own by VMware, and not just a technical concept of VSAN
Judas Freaking Priest.
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@dave247 said in I don't really get the point of SAN snapshots:
ok so lets say I didn't have a SAN and I didn't want to use vSAN or whatever.
There are basically four possible choices. This isn't about what is good or bad, just what is theoretically possible....
- Local storage (storage that connects without going over the network.)
- SAN (storage that connects over the network).
Then of each of those, they can be replicated or not replicated.
So you end up with...
- Plain SAN
- Replicated SAN
- Plain Local Storage
- Replicated Local Storage
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@dave247 said in I don't really get the point of SAN snapshots:
Just a SAN that's virtualized. VMware's vSAN wasn't even the first. Starwind's vSAN is older, for example. And lots of us were building vSANs back around 2005 or earlier. It was common to do it back then, especially in labs.
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@dave247 said in I don't really get the point of SAN snapshots:
ok so lets say I didn't have a SAN and I didn't want to use vSAN or whatever. Is there another good method, such as maybe having two physical Windows servers basically serving up mirrored storage via iSCSI or FCoE?
So now that we know you meant VMware's vSAN product...
The big alternative (and assumed starting point for most of the SMB) is Starwind vSAN. It's available for free and in paid versions with support.
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@scottalanmiller said in I don't really get the point of SAN snapshots:
@dave247 said in I don't really get the point of SAN snapshots:
ok so lets say I didn't have a SAN and I didn't want to use vSAN or whatever. Is there another good method, such as maybe having two physical Windows servers basically serving up mirrored storage via iSCSI or FCoE?
So now that we know you meant VMware's vSAN product...
The big alternative (and assumed starting point for most of the SMB) is Starwind vSAN. It's available for free and in paid versions with support.
Well it's not even that I "meant VMware's vSAN product". I just assumed that's what we were talking about when "VSAN was mentioned", which clearly it is not.
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@scottalanmiller said in I don't really get the point of SAN snapshots:
@dave247 said in I don't really get the point of SAN snapshots:
ok so lets say I didn't have a SAN and I didn't want to use vSAN or whatever.
There are basically four possible choices. This isn't about what is good or bad, just what is theoretically possible....
- Local storage (storage that connects without going over the network.)
- SAN (storage that connects over the network).
Then of each of those, they can be replicated or not replicated.
So you end up with...
- Plain SAN
- Replicated SAN
- Plain Local Storage
- Replicated Local Storage
ok thanks for clearing that up.
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@dave247 if you want to play at home, you can do Starwind vSAN, Gluster, and DRBD all pretty easily for free just to see how they physically work. Can be a fun experiment.
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@scottalanmiller said in I don't really get the point of SAN snapshots:
@dave247 if you want to play at home, you can do Starwind vSAN, Gluster, and DRBD all pretty easily for free just to see how they physically work. Can be a fun experiment.
How/where?
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@dave247 said in I don't really get the point of SAN snapshots:
@scottalanmiller said in I don't really get the point of SAN snapshots:
@dave247 if you want to play at home, you can do Starwind vSAN, Gluster, and DRBD all pretty easily for free just to see how they physically work. Can be a fun experiment.
How/where?
Setup your hypervisor of choice and use StarWinds vSAN solution. They have deployment guides right on their website.
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@dave247 said in I don't really get the point of SAN snapshots:
@scottalanmiller said in I don't really get the point of SAN snapshots:
@dave247 if you want to play at home, you can do Starwind vSAN, Gluster, and DRBD all pretty easily for free just to see how they physically work. Can be a fun experiment.
How/where?
Well let's use Gluster as an example. Gluster runs on Linux (and maybe a few other things, never looked beyond Linux for it.) So that means you can use it with KVM, LXC, Xen, or VirtualBox for example.
Gluster wants three nodes or more. So pick your Linux... CentOS, Fedora, Ubuntu, etc. And do three VMs and build a Gluster Cluster (and see it out loud for extra fun.) Then find other fun things to say to people at work like "I'm off to muster a Gluster Cluster."
Gluster will work just fine (if a tad slow) with just a small slice of storage, three VMs, and all built on the same underlying disk(s). You can do it on a laptop. Obviously, just for learning.
No need for "real" storage beneath it. It will work exactly the same in a lab scenario.
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So Gluster seems like a solid solution in a lot of cases, but for performance workloads that can scale up, you'd likely want to use the Distributed Striped Glusterfs Volume, but this doesn't provide any redundancy, just a performance boost.
And would require* a backup solution of some sort.
AKA an agent on your VM to take backups at the file level so anything could be restored.
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@DustinB3403 said in I don't really get the point of SAN snapshots:
So Gluster seems like a solid solution in a lot of cases,
It's a pretty stock "go to" for this stuff. Very broadly used. RHEV uses it by default. Which means oVirt does, too.
