Asklemmy

43397 readers

1398 users here now

A loosely moderated place to ask open-ended questions

Search asklemmy 🔍

If your post meets the following criteria, it's welcome here!

Open-ended question
Not offensive: at this point, we do not have the bandwidth to moderate overtly political discussions. Assume best intent and be excellent to each other.
Not regarding using or support for Lemmy: context, see the list of support communities and tools for finding communities below
Not ad nauseam inducing: please make sure it is a question that would be new to most members
An actual topic of discussion

Looking for support?

Looking for a community?

Lemmyverse: community search
sub.rehab: maps old subreddits to fediverse options, marks official as such
[email protected]: a community for finding communities

~Icon~ ~by~ ~@Double_[email protected]~

founded 5 years ago

MODERATORS

[email protected]

Is RAID still needed? (programming.dev)

submitted 5 months ago by [email protected] to c/[email protected]

67 comments fedilink hide all child comments

Me and my friend were discussing this the other day about how he said RAID is no longer needed. He said it was due to how big SSDs have gotten and that apparently you can replace sectors within them if a problem occurs which is why having an array is not needed.

I replied with the fact that arrays allow for redundancy that create a faster uptime if there are issues and drive needs to be replaced. And depending on what you are doing, that is more valuable than just doing the new thing. Especially because RAID allows redundancy that can replicate lost data if needed depending on the configuration.

What do you all think?

you are viewing a single comment's thread
view the rest of the comments

[–] [email protected] 11 points 5 months ago (1 children)

Its very much still needed and heavily utilised in the enterprise world. Volume size is usually the lowest priority when it comes to arrays, redundancy and IOPS (the amount of concurrent transactions to the storage) is typically the priority. The exception here would be backup and archive storage, where IOPS is less important and volume size is more important.

As far as replacing sectors goes, I've never heard of this and I might just be ignorant on the subject but as far as I know you can't "replace" a bad sector. Only mark it as bad and not use it, and whatever was there before is gone. This has existed since HDD days. This is also why we use RAID - parity across disks to protect data.

Generally production storage will be in RAID-10, and backup/archive storage in RAID-6 or in some cases RAID-60 but I'm personally not a fan.

You also would consider how many disks are in the volume because there is a sweet spot. Too many disks = higher likelihood of total array failure due to simultaneous disk failures and more data loss in the event it does, but too few disks and you won't have good redundancy, capacity or performance either (depending on RAID level).

The biggest change I see in RAID these days is moving away from hardware RAID cards and into software-based solutions like Microsoft Storage Spaces, md, ZFS and similar. These all have their own way of doing things and some can even synchronise the data with other hosts.

Hope this helps!

[–] [email protected] 4 points 5 months ago

As far as replacing sectors goes, I've never heard of this and I might just be ignorant on the subject but as far as I know you can't "replace" a bad sector.

Ssds maintain stats on cell writes and move data when a cell nears it end. They keep spare capacity hidden from end users for this. Not using part of the drive increases also this spare capacity.

However ssds do fail and moving data to spare cells doesn't change that.