alt Hacker NewsSomething that's interested me is how hard drive capacities have continuously gone up, but read and write speeds have not really changed. To the point where it would take multiple days to read these new high capacity drives.
I wonder what the use case for them is, they aren't ideal for RAID as they would take far too long to rebuild the array in a drive failure, but they also aren't great for long term cold storage. Perhaps they are ideal for periodic backups where you want to take a daily 1TB backup of a server or CCTV where you don't really care about backing up the data as it's all deleted on schedule anyway.
Replies
For one, home servers can go on maintenance mode (read only?) for a day or two, it will be fine most of the time.
In bigger applications, you have enough redundancy to allow one or two nodes to go down for a while. If a company had terabytes upon terabytes of critical data, having a multi-tiered storage would make sense, even of a full backup restore would take a days.on some tiers.
I imagine that there is a ton of data in the "would be nice to retain but not so critical as to warrant a constant backup" category. Alternatively stuff that requires large storage, but only occasional small writes, so incremental backups are feasible.
Most of the data on my NAS is of that form.
you can use redundancy where the recovery time doesn't scale with size
You use them for backups, data archiving, or object storage with triple parity RAID or erasure coding. The combined bandwidth of dozens to hundreds of magnetic hard drives is pretty decent.
Speeds do go up with density. Take an empty 4 TB drive and an empty 16 TB drive, and then write and read 2 TB of data to both of them. Since the platters on the 16 TB one are that much denser, you go over a lot more blocks in a single spin than the 4 TB one.
Spinning rust is still the only cost effective answer to redundant 10+ tb storage. If you have 4+ disks, use raid 6 or raid 10 and you get decent fault tolerance too. Raid 10 also increases write performance but it's a bit less robust imo and more expensive per gb.
As for speed it's mainly tied to rpm and the market decided no one wants higher failure rates / lower mtbf for marginal speed gains.
If you need speed and capacity, throw an ssd or two in front of a raid disk array for caching with primocache or whatever.