[phonon]

EBS data is backed up in multiple redundant ways (using erasure encoding I think).

Local storage is not intended for permanent storage, and is more use at your own risk. That's also why most of the new EC2 instances don't even support local storage.

Availability =/= durability of course

[problems]

EBS is incredibly expensive and slow, not really a good solution. It'd be nice if they offered a better local storage option.

[phonon]

Incredibly expensive and slow compared to what? A 500 GB SSD (gp2) costs $50/m, and has 1500 - 3000 IOPS. It's okay for most loads.

For higher performance, you can use

1. EBS Provisioned IOPS (kind of expensive)

2. Aurora (for DB use)

3. The new I3 instances (super fast local storage at a reasonable price.)

[tomc1985]

That's the cost of a new 500GB SSD per month! For the cost of three months' EBS storage and a couple of hours you could setup your own RAID array with a spare for backups and possibly get better uptimes than Amazon :P

[problems]

Not to mention you'll get 3-5x better IOPS off a dedicated SSD.

I guess this just boils down again to Amazon not being cost effective enough for my use case in yet another way.

[phonon]

Actually, you can get way more than 3-5x better IOPS on your own SSD! Different types of storage have different types of trade-offs. EBS is great for some things, slow and overpriced for others...

[phonon]

Huh? What kind of 500 GB SSD costs $50? And again--500 GB on EBS is not stored on 500 GB of flash...they use erasure coding and distribute it over ~3x as much, roughly.

Oh, and good luck creating snapshots of your home RAID!

[problems]

> Huh? What kind of 500 GB SSD costs $50?

Definitely not $50 to my knowledge but for ~$170 you can get a Samsung 850 EVO which is rated for 98k IOPS. They're fairly reliable drives and much, much faster than anything you'll get on EBS. You could be running that full 3x replication in less than a year of paying for EBS.

> Oh, and good luck creating snapshots of your home RAID!

LVM, ZFS and Btrfs all do snapshotting quite nicely. FreeNAS - commonly used for consumer grade NASes will automatically manage ZFS snapshots for you too. Amazon will sell you extra space to store snapshots, sure, but increasing the size of your devices usually solves that problem. And quite cost effectively as you can probably tell by now...

[phonon]

...and Dropbox can be replaced with SFTP and rsync. Can you roll your own? Sure. Will it work as reliably and effectively as EBS? Can I scale it easily? How many people are comfortable using snapshots on their own?

[Sanddancer]

Not really that hard.

zfs snap tank/data@$(date '+Y%m%d')

zfs send tank/data@$(date '+Y%m%d') | zfs recv backup/data

advanced magic for off-system backup

zfs send tank/data@$(date '+Y%m%d') | ssh cheapdiskserver zfs recv tank/data

[Dylan16807]

> 1500 - 3000 IOPS

So about as many as this SD card, and nothing compared to a real SSD.

[phonon]

In practice, it's actually fine for most purposes. It's equivalent to multiple striped 15K RPM magnetic disks, which used to be high-end enterprise storage a few years ago.

SD cards have much worse write IOPS.

[Dylan16807]

> In practice, it's actually fine for most purposes.

It is, yes, but I wouldn't refer to it as comparable to an SSD.

> SD cards have much worse write IOPS.

Surprisingly not! Testing in ATTO I got read and write speeds that were almost identical, and a peak of 2000 IOps.

[phonon]

>It is, yes, but I wouldn't refer to it as comparable to an SSD.

EBS (gp2) is flash based, has far better performance than high end magnetic disks, with excellent latency and consistent performance. So, it's more comparable to SSD than anything else.

>Surprisingly not! Testing in ATTO I got read and write speeds that were almost identical, and a peak of 2000 IOps.

Really? Were you looking at 4K write? Typically that would be under 1 MB/s for an SD card.

[foxylion]

I think most people rely on EBS and are happy with it. Sure it depends on the use case, but I think it works for most use cases.