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Comment by jcampbell1 | Hacker News Reader

I know there is this theory that server hardware needs to be more durable therefore you should pay an order of magnitude more, but all of my server workloads are write somewhat frequently, read randomly, and delete almost never. It is my understanding, that commodity consumer SSDs should work fine for this workload.

I assume Digital Ocean is using consumer SSDs, and it feels like it shouldn't be a problem with the exception of the bad neighbor issue.

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Actually I thought it was going the other way: "Old school" is that server hardware should be reliable so it doesn't go down, and "New school" is that hardware should be cheap and there should be a lot of it so that if one server goes down we don't care.

Both DigitalOcean and Linode are in the "old school" camp. They are in the business of providing reliable hosting at good prices.

My question was along the lines of: Using consumer HDs in servers is a disaster because the 24/7 read workload eventually breaks spinning platters. Server grade magnetic disks are a must in servers. Consumer grade SSDs are acceptable in servers because they don't wear out from 24/7 reads. Consumer SSDs fail from constant deletes+writes. Server workloads don't produce many deletes, therefore it is safe to put consumer SSDs in servers.

Is the above correct? Is the premium for server grade SSDs a myth? Should I feel safe using Digital Ocean under the assumption they are using consumer SSDs for multi-tenant servers?

Some workloads are write-intensive and some aren't. For a hosting provider there's no way to know what the customers are going to do. I would expect that SSDs attract customers who are going to actually give them a workout, though.

> Some workloads are write-intensive and some aren't.

Did you read what I wrote? Do you mean delete-intensive?

I don't think there's any truth to your notion that deletes are somehow worse for a solid state drive than other kinds of writes. Overwriting a sector has the same effect on longevity as erasing it and filling it up again, but in the latter case, you can use the ATA TRIM command to defer the flash block erase latency (which is significantly higher than the flash program latency). The only way in which deletes are "bad" is if you're comparing to a workload that fills the drive once and then moves on to fill a different drive - but that's not a fair comparison against doing all the writes to the same drive.

Different workloads can somewhat affect how much write amplification results from the wear leveling, but the best-case there actually is to have no long-lived data on the drive, ie. lots of deletes.

I think he's assuming that since it's actually rewritten flash-memory bits that degrade, if you don't delete data, then you don't rewrite. So without deletes, all writes simply fill more of the drive and you shouldn't see degradation.

Modern flash drives do indeed try to level the writes across all bits, but he's talking about work-loads that don't rewrite at all.

I wouldn't call an application that writes once and never deletes anything on the hard drive a write-intensive workload. Filling up a SSD with write-once data means paying well over 50¢/GB for your writes, which isn't something you can do if you are "write-intensive" -- if you're writing 100x the capacity of the drive over its lifetime, then you are really write-intensive, at which point the distinction between delete-intensive and write-intensive is nearly nonexistent for obvious reasons.

All the dedicated server providers I know, do in fact use "consumer" HDs in systems, but allow you to spend more to use "server" HDs.

And, a properly equipped server for the workload being used, should not have its disks being used a lot, since loads tend to be spiky. So they should be busy during peak periods but much less busy other times.

> They are in the business of providing reliable hosting at good prices.

Which is also possible in the "new school" camp…

Reading, writing, and deleting all degrade SSDs due to wear leveling. It's a common misconception that only deleting files degrades SSDs. I'm guessing this is what linode is getting at here.

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