VMWare, Backup and VCB
(The Good, The Bad and The Ugly)
I hate Backup.
Actually, that’s not entirely true. I hate having to ‘do’ backups. After too many years in IT, I know the value of having good backups. But it doesn’t change the fact that I hate having to perform and manage them.
I love VMWare.
Without a shadow of doubt, I love working with VMWare for the simple fact that it makes my life easier.
So now I find myself in the dubious position of having the reconcile my love / hate relationship between VMWare and Backup. In my role as a Consultant as Scale Abilities, I’m often asked by clients what they should do with regards to VMWare backups. How long is that piece of sting..?
The problem is that there are almost too many ways to address the question. Agents in the VM Guest? Tape or disk? D2D2T? SAN Snapshots? Fibre attached or iSCSI? Vendor A vs Vendor B? What’s the recommended ‘Best Practice’?
As a company, we’ve banned the use of the phrase ‘Best Practice’, because at the end of the day, every client’s situation is different. What you should be asking is, what’s the ‘Right Practice’.
The ‘Right Practice’ is a lot of cases is the balance between cost vs functionality. I like to keep the costs low, as do the majority of our clients. So this is why VMWare’s Consolidated Backup (VCB) is often the backup choice in many situations.
I like it, because one of the tools, vcbMounter, is included in ESX and it lets me take backups. This seems like a good start for a backup tool…
For myself, I like the simplicity of just taking a full image-based backup of my VMs. Then I’ve got everything I need should a want to restore them. You can keep your incremental / differential backups; I’m sure they have their place, but I want the whole thing, every time.
I also don’t like tape (picky aren’t I?). The stuff always keeps going wrong, which isn’t a good recommendation for a backup technology. It’s also really, really expensive.
LTO4 tapes, which hold about 800GB native, are about £50 each. Doesn’t sound like much right? But what about the cost of the LTO drive? Or more normally, the cost of an autoloader as no-one want to be swapping tapes at midnight…
So say you had to backup 2TB of data, you’d probably need something like:
3 x LTO4 Tapes = £150.00
1 x 1/8 HP LTO4 Autoloader = £3200.00
1 x SAS HBA = £100.00
1 x NBD Hardware Support = £300.00
Total = £3750.00
That’s your initial investment to backup 2TB data. If you want to keep historical backups, it’s £150 each time for another set of 3 LTO4 Tapes.
So what’s the alternative? Well, I’m a big fan of disk. You can now pickup a small 2TB NFS NAS for less than £400.
So with disk, what do we need to backup 2TB of data?:
1 x 2TB NFS NAS = £400
Total = £400
Hummmm… I’d struggle to justify the tape solution to a client!
Need to keep historical backups? Cool, buy another NAS. Buy another 8 and you’ll still be better off!
Want to keep monthly backups? Well, that’s 36 LTO4 Tapes (3 per month), so now your backup costs are:
36 x LTO4 Tapes = £1800.00
1 x 1/8 HP LTO4 Autoloader = £3200.00
1 x SAS HBA = £100.00
1 x NBD Hardware Support = £300.00
Total = £5400.00
The disk / NAS costs are still less than that of tape:
12 x 2TB NFS NAS = £4800.00
Total = £4800.00
Oh yes, and that’s just hardware costs… Backup to tape almost certainly means that you need some backup software at some stage, so just throw another £500-£1000 in there. And of course, we all know how reliable those tapes are… They never break do they?
Why is all of this important? (Besides the cost saving aspect) Well, it means that with tape out of the equation, we can just use vcbMounter to make our backups straight to disk. Yay!
Again, there are still plenty of ways to skin the cat, but my preference is:
1. Mount the NAS as an NFS datastore
2. Run your vcbMounter backups
3. Unmount the NAS
All of this is easily scriptable and can be done on the ESX Server.
The performance is dependant on a combination of your NAS and ESX Server CPU.
As an example, I know that our NetApp SAN will happily do 900 Mbit/s without breaking a sweat. So using this for testing, means that we can eliminate NAS performance. So backing up a 20GB VM Guest, the network performance looks like this:
Although it’s not a very scientific test, checking out the CPU performance on ESX server, shows that the ‘host’ process is hammering the CPU. But interesting, it seems to be limited to one core, so actually may not impact VM Guest performance as much as you might think…
The key to all of this is to make sure that you get the ‘right’ NAS, that supports NFS at the performance levels you need.
Some cheaper NAS devices, which claim to support NFS, are sadly limited in their performance. Make sure that you do some testing first to ensure that you get what you need.
And remember, there’s no ‘Best Practice’, only ‘Right Practice’.
Simples.
G.
(The Good, The Bad and The Ugly)
I hate Backup.
Actually, that’s not entirely true. I hate having to ‘do’ backups. After too many years in IT, I know the value of having good backups. But it doesn’t change the fact that I hate having to perform and manage them.
I love VMWare.
Without a shadow of doubt, I love working with VMWare for the simple fact that it makes my life easier.
So now I find myself in the dubious position of having the reconcile my love / hate relationship between VMWare and Backup. In my role as a Consultant as Scale Abilities, I’m often asked by clients what they should do with regards to VMWare backups. How long is that piece of sting..?
The problem is that there are almost too many ways to address the question. Agents in the VM Guest? Tape or disk? D2D2T? SAN Snapshots? Fibre attached or iSCSI? Vendor A vs Vendor B? What’s the recommended ‘Best Practice’?
As a company, we’ve banned the use of the phrase ‘Best Practice’, because at the end of the day, every client’s situation is different. What you should be asking is, what’s the ‘Right Practice’.
The ‘Right Practice’ is a lot of cases is the balance between cost vs functionality. I like to keep the costs low, as do the majority of our clients. So this is why VMWare’s Consolidated Backup (VCB) is often the backup choice in many situations.
I like it, because one of the tools, vcbMounter, is included in ESX and it lets me take backups. This seems like a good start for a backup tool…
For myself, I like the simplicity of just taking a full image-based backup of my VMs. Then I’ve got everything I need should a want to restore them. You can keep your incremental / differential backups; I’m sure they have their place, but I want the whole thing, every time.
I hate tape.
The stuff always keeps going wrong, which isn’t a good recommendation for a backup technology. It’s also really, really expensive. You don’t believe me?
LTO4 tapes, which hold about 800GB native, are about £50 each. Doesn’t sound like much right? But what about the cost of the LTO drive? Or more normally, the cost of an autoloader as no-one want to be swapping tapes at midnight…
So say you had to backup 2TB of data, you’d probably need something like:
- 3 x LTO4 Tapes = £150.00
- 1 x 1/8 HP LTO4 Autoloader = £3200.00
- 1 x SAS HBA = £100.00
- 1 x NBD Hardware Support = £300.00
- Total = £3750.00
That’s your initial investment to backup 2TB data. If you want to keep historical backups, it’s £150 each time for another set of 3 LTO4 Tapes.
So what’s the alternative? Well, I’m a big fan of disk. You can now pickup a small 2TB NFS NAS for less than £400.
With disk, what do we need to backup 2TB of data?:
- 1 x 2TB NFS NAS = £400
- Total = £400
Hummmm… I’d struggle to justify the tape solution to a client!
Need to keep historical backups? Cool, buy another NAS. Buy another 8 and you’ll still be better off!
Want to keep monthly backups? Well, that’s 36 LTO4 Tapes (3 per month), so now your backup costs are:
- 36 x LTO4 Tapes = £1800.00
- 1 x 1/8 HP LTO4 Autoloader = £3200.00
- 1 x SAS HBA = £100.00
- 1 x NBD Hardware Support = £300.00
- Total = £5400.00
The disk / NAS costs are still less than that of tape:
- 12 x 2TB NFS NAS = £4800.00
- Total = £4800.00
Oh yes, and that’s just hardware costs… Backup to tape almost certainly means that you need some backup software at some stage, so just throw another £500-£1000 in there. And of course, we all know how reliable those tapes are… They never break do they?
Why is all of this important? (Besides the cost saving aspect) Well, it means that with tape out of the equation, we can just use vcbMounter to make our backups straight to disk. Yay!
Again, there are still plenty of ways to skin the cat, but my preference is:
- Mount the NAS as an NFS datastore
- Run your vcbMounter backups
- Unmount the NAS
All of this is easily scriptable and can be done on the ESX Server.
The performance is dependant on a combination of your NAS and ESX Server CPU.
As an example, I know that our NetApp SAN will happily do 900 Mbit/s without breaking a sweat. So using this for testing, means that we can eliminate NAS performance. So backing up a 20GB VM Guest, the network performance looks like this:
VCB - 20GB VM Guest Backup
Although it’s not a very scientific test, checking out the CPU performance on ESX server, shows that the ‘host’ process is hammering the CPU. But interesting, it seems to be limited to one core, so actually may not impact VM Guest performance as much as you might think…
The key to all of this is to make sure that you get the ‘right’ NAS, that supports NFS at the performance levels you need.
Some cheaper NAS devices, which claim to support NFS, are sadly limited in their performance. Make sure that you do some testing first to ensure that you get what you need.
And remember, there’s no ‘Best Practice’, only ‘Right Practice’.
Simples.
G.
