this post was submitted on 18 Oct 2024
355 points (99.7% liked)
Technology
59627 readers
2911 users here now
This is a most excellent place for technology news and articles.
Our Rules
- Follow the lemmy.world rules.
- Only tech related content.
- Be excellent to each another!
- Mod approved content bots can post up to 10 articles per day.
- Threads asking for personal tech support may be deleted.
- Politics threads may be removed.
- No memes allowed as posts, OK to post as comments.
- Only approved bots from the list below, to ask if your bot can be added please contact us.
- Check for duplicates before posting, duplicates may be removed
Approved Bots
founded 1 year ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
Assuming that these have fairly impressive 100 MB/s sustained write speed, then it's going to take about 93 hours to write the whole contents of the disk - basically four days. That's a long time to replace a failed drive in a RAID array; you'd need to consider multiple disks of redundancy just in case another one fails while you're resilvering the first.
My 16TB ultrastars get upwards of 180MB/s sustained read and write, these will presumably be faster than that as the density is higher.
I'm guessing that only works if the file is smaller than the RAM cache of the drives. Transfer a file that's bigger than that, and it will go fast at first, but then fill the cache and the rate starts to drop closer to 100 MB/s.
My data hoarder drives are a pair of WD ultrastar 18TB SAS drives on RAID1, and that's how they tend to behave.
This is for very long sustained writes, like 40TiB at a time. I can't say I've ever noticed any slowdown, but I'll keep a closer eye on it next time I do another huge copy. I've also never seen any kind of noticeable slowdown on my 4 8TB SATA WD golds, although they only get to about 150MB/s each.
EDIT: The effect would be obvious pretty fast at even moderate write speeds, I've never seen a drive with more than a GB of cache. My 16TB drives have 256MB, and the 8TB drives only 64MB of cache.