Can I use multi-attach in Windows

0

I am trying to decipher the following statement (first bullet from here):

You can attach a volume that is Multi-Attach enabled to Windows instances, but the operating system does not recognize the data on the volume that is shared between the instances, which can result in data inconsistency.

If OS doesn't recognize the data, then data inconsistency is least of my concerns, no? To summarize can I use multi-attach with Windows? Or the only option is FSx, that requires full-blown AD and therefore drives the price up?

profile picture
virshu
asked a month ago31 views
2 Answers
0

Yes, you can use multi-attach with Windows but (as the documentation says) but the operating system is expecting to have exclusive access to the disks that are mounted. If there are two writers on the same disk they won't recognise each other and that will mean that the volume will become inconsistent in some way. If you mounted the disk read-only the challenge is that the operating system doesn't expect any other writers so will not recognise new data that is written to it without you dismounting and remounting the volume.

Rather than recommend FSx as the next step, it would help if you could describe what you're trying to achieve - that may get a better answer.

profile picture
EXPERT
answered a month ago
profile picture
EXPERT
Rob_H
reviewed a month ago
  • the use case is pretty straightforward... 2 application servers behind load balancer that allows the users to upload images, and images need to be available to users that happen to access the other server.

  • If it were me I'd store the images in S3. Easy, scalable, less expensive access for download. No need to maintain a shared filesystem.

  • What Brettski mentioned is absolutely correct. Do Not use multi-attach in the method you've described. If both machines attempt to write to the same blocks, you'll corrupt the drive and lose data. Using S3 or FSx is going to be a much better fit. Cost wise, S3 is your best bet.

  • I appreciate the advice about S3. But I'll ask you to trust that we made the decision of UNC path vs. S3 after considering pros and cons. So, the choice is really between AD+FSx vs multi-attach. What I am reading from Rob-H comment, is the same that I am reading from documentation linked in the question - namely, that multi-attach is not supported on Windows instances. I can assure that different instances don't edit the same files; but I can't assure which blocks instance will choose for writing a new file. Hopefully, AWS will support shared drives in Windows better in the future...

0

It looks like "multi-attach" drive isn't really shared among the instances. So, the premise of my question is wrong. The only way to share the drive among Windows EC2 instances is FSx. Disappointing...

profile picture
virshu
answered a month ago
  • Alternatively; don't use Windows. Use Linux instead which does support multi-attach. That's an easy thing to say and not an easy thing to do but it's a way to do what you want to do.

  • :) yes - easier said than done! Also, if I use Linux, EFS is much cheaper and IMHO better than multi-attach. The best difference is that you don't need to provision EFS (unlike FSx or multi-attach EBS) - you really pay only for what you use!

You are not logged in. Log in to post an answer.

A good answer clearly answers the question and provides constructive feedback and encourages professional growth in the question asker.

Guidelines for Answering Questions