Replication Options for KVM to DR Site



  • @scottalanmiller said in Replication Options for KVM to DR Site:

    It's Network RAID. No RAID has versioning. If you want versioning, which is a great thing to have, that happens at a higher level. You can still do it, it's just not included in DRBD.

    Exactly! Saying RAID is DR, is like saying it's the same as backup - only noobs do that.



  • @scottalanmiller said in Replication Options for KVM to DR Site:

    @dyasny said in Replication Options for KVM to DR Site:

    that's because DRBD isn't a DR tool, it's a block replication tool. All real DR solutions have granularity and versioning. SRM, Zerto, NeverFail, even old WanSync - all of them could do it. DRBD can only sync blocks, nothing else. This is not DR.

    Like everything in the UNIX world, you build solutions from individual blocks. In the Windows world, people assume all solutions will do a single task and be pre-assembled for them. So you find a "product" that does what you need.

    In the UNIX world, it is generally assumed that you'll understand the tools and the concepts and use the existing tools transparently and put together what you need it to do.

    So nothing is a DR tool in UNIX, but DRBD is a perfectly valid building block to handle one of the pieces that becomes a DR solution.

    To paraphrase John Nicholson of VMware... disaster recovery is something that you do, not something that you buy.

    Well, no. DRBD (or any replication or storage sharding really) can be used if you want to protect yourself from a storage failure, just like with RAID you protect yourself from a disk failure. A DR solution should be able to bring you back from an outage. There is a huge difference there. Tape backup is more of a DR solution than RAID or storage replication. That's the point I'm trying to make.



  • @dyasny said in Replication Options for KVM to DR Site:

    @scottalanmiller said in Replication Options for KVM to DR Site:

    @dyasny said in Replication Options for KVM to DR Site:

    that's because DRBD isn't a DR tool, it's a block replication tool. All real DR solutions have granularity and versioning. SRM, Zerto, NeverFail, even old WanSync - all of them could do it. DRBD can only sync blocks, nothing else. This is not DR.

    Like everything in the UNIX world, you build solutions from individual blocks. In the Windows world, people assume all solutions will do a single task and be pre-assembled for them. So you find a "product" that does what you need.

    In the UNIX world, it is generally assumed that you'll understand the tools and the concepts and use the existing tools transparently and put together what you need it to do.

    So nothing is a DR tool in UNIX, but DRBD is a perfectly valid building block to handle one of the pieces that becomes a DR solution.

    To paraphrase John Nicholson of VMware... disaster recovery is something that you do, not something that you buy.

    Well, no. DRBD (or any replication or storage sharding really) can be used if you want to protect yourself from a storage failure, just like with RAID you protect yourself from a disk failure. A DR solution should be able to bring you back from an outage. There is a huge difference there. Tape backup is more of a DR solution than RAID or storage replication. That's the point I'm trying to make.

    Yes, we use the term DA vs DR.

    RAID (including Network RAID like DRBD) is Disaster Avoidance, backups are part of Disaster Recovery.

    One is to prevent a disaster, the other is to recovery from a disaster.



  • @scottalanmiller said in Replication Options for KVM to DR Site:

    @dyasny said in Replication Options for KVM to DR Site:

    @scottalanmiller said in Replication Options for KVM to DR Site:

    @dyasny said in Replication Options for KVM to DR Site:

    that's because DRBD isn't a DR tool, it's a block replication tool. All real DR solutions have granularity and versioning. SRM, Zerto, NeverFail, even old WanSync - all of them could do it. DRBD can only sync blocks, nothing else. This is not DR.

    Like everything in the UNIX world, you build solutions from individual blocks. In the Windows world, people assume all solutions will do a single task and be pre-assembled for them. So you find a "product" that does what you need.

    In the UNIX world, it is generally assumed that you'll understand the tools and the concepts and use the existing tools transparently and put together what you need it to do.

    So nothing is a DR tool in UNIX, but DRBD is a perfectly valid building block to handle one of the pieces that becomes a DR solution.

    To paraphrase John Nicholson of VMware... disaster recovery is something that you do, not something that you buy.

    Well, no. DRBD (or any replication or storage sharding really) can be used if you want to protect yourself from a storage failure, just like with RAID you protect yourself from a disk failure. A DR solution should be able to bring you back from an outage. There is a huge difference there. Tape backup is more of a DR solution than RAID or storage replication. That's the point I'm trying to make.

    Yes, we use the term DA vs DR.

    RAID (including Network RAID like DRBD) is Disaster Avoidance, backups are part of Disaster Recovery.

    One is to prevent a disaster, the other is to recovery from a disaster.

    Exactly. This is why DRBD is not a DR solution, like I've been saying all along. The problem with any kind of avoidance is that it can only target a limited number of potential problems, while a recovery solution covers everything.



  • @dyasny said in Replication Options for KVM to DR Site:

    while a recovery solution covers everything

    Well, in theory, lol. Nothing really covers "everything". There is always a scope, even if that is meteor strike or interplanetary warfare.

    Having worked on Wall St. where scopes are way bigger and people actually do DR planning while addressing things like entire regional destruction (e.g. all of a continent lost) is what most people would consider "ridiculously over the top" for DR planning. But to others, it's just normal scope.



  • @scottalanmiller said in Replication Options for KVM to DR Site:

    @dyasny said in Replication Options for KVM to DR Site:

    while a recovery solution covers everything

    Well, in theory, lol. Nothing really covers "everything". There is always a scope, even if that is meteor strike or interplanetary warfare.

    Having worked on Wall St. where scopes are way bigger and people actually do DR planning while addressing things like entire regional destruction (e.g. all of a continent lost) is what most people would consider "ridiculously over the top" for DR planning. But to others, it's just normal scope.

    LOL - for most, if a region is lost, so is their business.



  • @Dashrender said in Replication Options for KVM to DR Site:

    @scottalanmiller said in Replication Options for KVM to DR Site:

    @dyasny said in Replication Options for KVM to DR Site:

    while a recovery solution covers everything

    Well, in theory, lol. Nothing really covers "everything". There is always a scope, even if that is meteor strike or interplanetary warfare.

    Having worked on Wall St. where scopes are way bigger and people actually do DR planning while addressing things like entire regional destruction (e.g. all of a continent lost) is what most people would consider "ridiculously over the top" for DR planning. But to others, it's just normal scope.

    LOL - for most, if a region is lost, so is their business.

    Right, but for others, it's not. Hence why scope is important. One company's scope versus another changes what is DA vs DR for one or the other.



  • @scottalanmiller I've worked for a few banks as well, nothing to be too proud of 🙂 Seriously though, when you recover it is up to you to build the infra and get everything ready for recovery, when you avoid you need to target specific issues you're avoiding. You can restore from backup in pretty much any reasonable scenario. You can't avoid every, even reasonable, scenario, this is why backups were invented.



  • @dyasny said in Replication Options for KVM to DR Site:

    You can't avoid every, even reasonable, scenario, this is why backups were invented.

    That's my point. Losing the backups as well. Backups still don't protect from everything. Not when you lose whole regions. There are events that take out your backups as well, even if they are stored in another country, for example.



  • @JaredBusch said in Replication Options for KVM to DR Site:

    @dyasny said in Replication Options for KVM to DR Site:

    Zerto

    Would never use, ever. Hacked ass shit.

    Irony. On-High where I am is having us look at Zerto.



  • @EddieJennings said in Replication Options for KVM to DR Site:

    On-High where I am is having us look at Zerto.

    It's not a business tool. It's officially unsupported and puts your VMware installation at risk. If you use Zerto, you dont' believe in VMware. It is strongly advised officially to never, ever consider.

    If you use it, you voluntarily suspend any support guarantees from everyone. It breaches every possible support position. Not that Vmware would use that as an excuse to not support you, VMware isn't like that, but any legal responsibility that you've paid for them to have is completely gone.



  • @scottalanmiller said in Replication Options for KVM to DR Site:

    @EddieJennings said in Replication Options for KVM to DR Site:

    On-High where I am is having us look at Zerto.

    It's not a business tool. It's officially unsupported and puts your VMware installation at risk. If you use Zerto, you dont' believe in VMware. It is strongly advised officially to never, ever consider.

    I think it's being considering for our Hyper-V environment, which is what's used for our Citrix stuff. It's not something within my sphere of influence.



  • @EddieJennings said in Replication Options for KVM to DR Site:

    I think it's being considering for our Hyper-V environment, which is what's used for our Citrix stuff. It's not something within my sphere of influence.

    No idea what it does there, but you'd think you'd want backups to be from a reliable vendor of all things.



  • @scottalanmiller said in Replication Options for KVM to DR Site:

    That's my point. Losing the backups as well. Backups still don't protect from everything. Not when you lose whole regions. There are events that take out your backups as well, even if they are stored in another country, for example.

    OK, lets go to the extremes, the planet gets hit by a dinosaur killing meteorite, we all go into a new ice age and die. DR becomes a non-issue. I thought I already mentioned the level-of-paranoia variable. IF you want to protect yourself from such an event - invest in sending backups to Mars and storing them there. But really, I thought we were having a meaningful conversation here, not a post apocalyptic scifi con



  • @scottalanmiller said in Replication Options for KVM to DR Site:

    It's not a business tool. It's officially unsupported and puts your VMware installation at risk. If you use Zerto, you dont' believe in VMware. It is strongly advised officially to never, ever consider.

    If you use it, you voluntarily suspend any support guarantees from everyone. It breaches every possible support position. Not that Vmware would use that as an excuse to not support you, VMware isn't like that, but any legal responsibility that you've paid for them to have is completely gone.

    Is that an official documented vmware policy? I wouldn't be surprised of course, they are horrible at actually being able to cope with competition, hence all the restrictions on benchmarking and comparisons.

    I'm not a fan of Zerto (for my own reasons, I wouldn't go near them, ever), but if vmware are basically selling you a product and then refuse to support it (even if support has been paid for) because you use an ISV for added functionality instead of paying for their own add-on, that's just ugly of them. Another reason to run away to other vendors, IMO.



  • @dyasny said in Replication Options for KVM to DR Site:

    Is that an official documented vmware policy? I wouldn't be surprised of course, they are horrible at actually being able to cope with competition, hence all the restrictions on benchmarking and comparisons.

    Yes, it is codified in their API documents. Zerto uses a kernel hook that is unofficial, unstable, and not supported. So it can cause any number of problems and anything that uses it is in violation of the support agreement.



  • @dyasny said in Replication Options for KVM to DR Site:

    I'm not a fan of Zerto (for my own reasons, I wouldn't go near them, ever), but if vmware are basically selling you a product and then refuse to support it (even if support has been paid for) because you use an ISV for added functionality instead of paying for their own add-on, that's just ugly of them.

    You can use any other vendor, just not hat one.



  • @scottalanmiller said in Replication Options for KVM to DR Site:

    You can use any other vendor, just not hat one.

    Wasn't aware of that, anywhere I can read about it (and maybe zerto's response as well)



  • @dyasny said in Replication Options for KVM to DR Site:

    @scottalanmiller said in Replication Options for KVM to DR Site:

    That's my point. Losing the backups as well. Backups still don't protect from everything. Not when you lose whole regions. There are events that take out your backups as well, even if they are stored in another country, for example.

    OK, lets go to the extremes, the planet gets hit by a dinosaur killing meteorite, we all go into a new ice age and die. DR becomes a non-issue. I thought I already mentioned the level-of-paranoia variable. IF you want to protect yourself from such an event - invest in sending backups to Mars and storing them there. But really, I thought we were having a meaningful conversation here, not a post apocalyptic scifi con

    But that was my point, what's considered a reasonable, rational risk scenario to an invest bank sounds to normal people to be similar to meteor level extinction events. Hence why the "backups have to cover everything possible" rule can't work, even if you add the caveat of "within rational scope", it is clear that Fortune 100 rational is SMB crazy. And what is F100 crazy, is still Wall St. rational. And what is Wall St crazy, is big government rational.

    Backups shouldn't stop being backups based on the impression of rational scope. A backup is a backup, the scope that it covers is its coverage scope. Otherwise no SMB's backups would be a backup to the enterprise, for example. But the viewpoint of the observer should not be the determination of what is or isn't a backup, but rather an intrinsic property of the backup itself. Otherwise, you force a crazy scope to happen and someone mentions meteors - which was my point.



  • @dyasny said in Replication Options for KVM to DR Site:

    @scottalanmiller said in Replication Options for KVM to DR Site:

    You can use any other vendor, just not hat one.

    Wasn't aware of that, anywhere I can read about it (and maybe zerto's response as well)

    AFAIK it's just in the software docs and Zerto ignores it because it is not in their interest to admit it, and Vmware doesn't bring it up because Zerto helps to sell VMware products so they mostly look the other way.



  • @scottalanmiller said in Replication Options for KVM to DR Site:

    But that was my point, what's considered a reasonable, rational risk scenario to an invest bank sounds to normal people to be similar to meteor level extinction events. Hence why the "backups have to cover everything possible" rule can't work, even if you add the caveat of "within rational scope", it is clear that Fortune 100 rational is SMB crazy. And what is F100 crazy, is still Wall St. rational. And what is Wall St crazy, is big government rational.

    Backups shouldn't stop being backups based on the impression of rational scope. A backup is a backup, the scope that it covers is its coverage scope. Otherwise no SMB's backups would be a backup to the enterprise, for example. But the viewpoint of the observer should not be the determination of what is or isn't a backup, but rather an intrinsic property of the backup itself. Otherwise, you force a crazy scope to happen and someone mentions meteors - which was my point.

    Lets agree on DR solutions being able (or striving to at least) cover disasters of whatever the scoped level is for a given business. With this in mind, avoidance techniques still have to target specific errors, while recovery solutions cover data loss from all of those, plus any other failure (within the scope, yes. Nothing will cover the failure of Earth remaining a livable planet).


Log in to reply