4 ms·

As someone who doesn't know AWS much, what are the major differences between this and EBS?

by positr0n 12y ago

zippergz 12y ago
You can mount the volume on more than one instance at the same time, which you can't do with EBS.
- artursapek 12y ago
  It's also hard to resize an EBS volume, right? This resizes itself automatically.
  - kolencherry 12y ago
    You have to create a snapshot of the EBS volume and create a new (larger) volume from said snapshot to grow the volume. Yep, this resizes automatically.
nkozyra 12y ago
As has been mentioned, EBS can only be mounted to one instance at a time. If you could mount it to multiple it would effectively be the same thing, but then you have all sorts of write-locking issues. As the rest of the comments also allude, a lot of the cloud-entrenched world has abandoned NFS, or at least in AWS circles. I'm not one of these people. Rather than relying solely on puppet->all instances to handle multiple deploys, the convenience of an NFS instance was appealing, so essentially I have a relatively small (read: medium) instance that does nothing but manage the deployment filesystems and allow new in-security groups to connect. I have often though of abandoning this for doing deploys in a more "modern" way but I'm still not sure what the benefit would be other than eliminating a minor source of shame. The analog here is running a MySQL or Postgres database in an instance prior to RDS. RDS provided enough benefit that the minor price difference in rolling your own no longer factored in. A more reliable, fault-tolerant and extensible file system is, like RDS, a huge upgrade. It may not be for everyone, but for some of us it's just another reason why AWS keeps making it hard to even look anywhere else.
- vizzah 12y ago
  Would it be a good idea to store Mysql db on EFS to be shared among load-balanced instances?
  - simonw 12y ago
    No, absolutely not. See the warning on http://dev.mysql.com/doc/refman/5.0/en/multiple-data-directories.html http://dev.mysql.com/doc/refman/5.0/en/multiple-data-directo...
  - nkozyra 12y ago
    As simonw points out, it produces a real problem with regard to MySQL and the way it handles its data source(s) in general, but more importantly, it's wholly unnecessary. The right way to do that (in AWS world) would be RDS accessible to all instances in the security group. This yields locking control to the application level and not the file system. For obvious reasons this makes a lot of sense. There are of course non-ACID / NoSQL solutions for which this might be an acceptable practice, but in general I'd say it's fraught with peril.
  - rev_bird 12y ago
    This idea got shot down pretty quick, but I love that it was asked. Coming up with potentially disastrous sideways use-cases for new toys is a favorite pastime of mine.

As someone who doesn't know AWS much, what are the major differences between this and EBS?

zippergz 12y ago

You can mount the volume on more than one instance at the same time, which you can't do with EBS.

artursapek 12y ago
It's also hard to resize an EBS volume, right? This resizes itself automatically.
- kolencherry 12y ago
  You have to create a snapshot of the EBS volume and create a new (larger) volume from said snapshot to grow the volume. Yep, this resizes automatically.

nkozyra 12y ago

As has been mentioned, EBS can only be mounted to one instance at a time. If you could mount it to multiple it would effectively be the same thing, but then you have all sorts of write-locking issues. As the rest of the comments also allude, a lot of the cloud-entrenched world has abandoned NFS, or at least in AWS circles. I'm not one of these people. Rather than relying solely on puppet->all instances to handle multiple deploys, the convenience of an NFS instance was appealing, so essentially I have a relatively small (read: medium) instance that does nothing but manage the deployment filesystems and allow new in-security groups to connect. I have often though of abandoning this for doing deploys in a more "modern" way but I'm still not sure what the benefit would be other than eliminating a minor source of shame. The analog here is running a MySQL or Postgres database in an instance prior to RDS. RDS provided enough benefit that the minor price difference in rolling your own no longer factored in. A more reliable, fault-tolerant and extensible file system is, like RDS, a huge upgrade. It may not be for everyone, but for some of us it's just another reason why AWS keeps making it hard to even look anywhere else.

vizzah 12y ago
Would it be a good idea to store Mysql db on EFS to be shared among load-balanced instances?
- simonw 12y ago
  No, absolutely not. See the warning on http://dev.mysql.com/doc/refman/5.0/en/multiple-data-directories.html http://dev.mysql.com/doc/refman/5.0/en/multiple-data-directo...
- nkozyra 12y ago
  As simonw points out, it produces a real problem with regard to MySQL and the way it handles its data source(s) in general, but more importantly, it's wholly unnecessary. The right way to do that (in AWS world) would be RDS accessible to all instances in the security group. This yields locking control to the application level and not the file system. For obvious reasons this makes a lot of sense. There are of course non-ACID / NoSQL solutions for which this might be an acceptable practice, but in general I'd say it's fraught with peril.
- rev_bird 12y ago
  This idea got shot down pretty quick, but I love that it was asked. Coming up with potentially disastrous sideways use-cases for new toys is a favorite pastime of mine.