How to copy RAM disk image to a backup server

Started by Thorsten

Thorsten

How to copy RAM disk image to a backup server   12 March 2021, 10:46

Dear all,

I searched for a long time to find a product like yours, which can mount a RAM disk and is also able to create an image file for restarting the server without losing data. This part works perfectly, just as I need it for a customers production server.

Because we need to offer a 100% safe backup, we have two identical servers. The first one is "hot", running production. The second one is a "cold" backup, which is turned on only if we have an error. To save the RAM disk image we use a QNAP NAS with RAID6 and connected by 10Gb fibre optics.

Now if I test the use of the RAM disk image for restoring the cold backup, I run into trouble while the RAM drive knows that it is not created by the same server. Do you have any solution to help me out with this problem? If yes, I shall buy two licences to finally have the absolute perfect cold backup solution for the critical customer data.

Thank you in advance.

Kind regards,
Thorsten
SoftPerfect Support forum - Ann avatar image
Ann

Re: How to copy RAM disk image to a backup server   12 March 2021, 10:59

Generally, having a RAM disk image in a network folder is not supported. The reason for it is that the RAM Disk software is initialised early in system boot, before the network becomes available. Another issue here is that if for some reason the image gets partially written or otherwise damaged, you will not be able to load its data to either server.

I am not entirely certain what you are trying to achieve, but this may be a better way:
  1. Have two servers, hot and cold. Both have an image stored on their own disks.
  2. Run rsync or a similar utility to continuously back up the image from the hot server to the NAS, and then from the NAS to the cold server.
  3. You can also set up incremental copies, to ensure you can recover the data even if a damaged image gets replicated to the NAS and the cold server.

An even better way may be not to use images at all. Instead, continuously replicate your data from the hot server RAM disk to the NAS, and then from the NAS to the cold server. This way the cold server should have the same data with only a small delay. And in this case there is no risk of a partially written or damaged image file.
Thorsten

Re: How to copy RAM disk image to a backup server   15 March 2021, 14:54

Thank you so much for the detailed answer. I'll try to describe our setup a bit more.

The disk image is kept locally, on disk C of the hot server. From time to time I copy the .IMG file to the NAS. When a backup is needed, I start the cold server and copy the .IMG file from the NAS to the local disk C of the cold server. If I restart, I end up with an error saying that the file could not be opened.

I am able to import the .IMG file, but I need to be able to mount it as a disk as well. Is there a fault with my setup?
Also, what kind of BackUp software would you recommend?

The work data at the customer side is more than 10GB and grows during working hours. We need to make sure that no data gets lost in case of any problems. So your RAM Disk with a local image and a backup copy would be my preferred solution.

If you can give me some help how to get the .IMG file form the hot server running on the cold server, that would be great.

Thank you and kind regards,
Thorsten
SoftPerfect Support forum - Ann avatar image
Ann

Re: How to copy RAM disk image to a backup server   15 March 2021, 15:14

As mentioned earlier, I don't recommend that you use an image file in this setup. It's an extra layer of complexity and an extra potential failure point. For example, if you start copying the image from the hot server to the NAS while the image is being written into, the resulting file will likely to be damaged (and this is probably the reason why you get that error).

In my opinion, you shouldn't be using images here. Instead, you could directly mirror the RAM disk contents to the NAS. Depending on the nature of your data, probably use Syncthing or Windows built-in tool called Robocopy (Robust File Copy).

With Robocopy you could do this:
robocopy R:\ \\YourNAS\Drive /MIR
This will mirror everything from RAM disk R:\ to a folder in your NAS. Then you could run Robocopy every minute or so, and that will keep the NAS copy almost identical to the contents of your RAM disk on the hot server.

Then, if the hot server fails, you can simply boot your cold server and do the opposite:
robocopy \\YourNAS\Drive R:\ /MIR
This will mirror the NAS folder to the newly initialised RAM drive on the cold server.
Thorsten

Re: How to copy RAM disk image to a backup server   16 March 2021, 10:02

Again many thanks for your perfect answer.

I will use your RAM Software because it will give me a huge improvement in speed with the data used on the RAM disk. I just ordered 256GB more RAM to get the disk much bigger compared to what it is at the moment.

Thank you again!

Keep safe.

Kind regards
Mit freundlichen Grüßen
Thorsten

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