RAIDZ3 optimal width (9, 10 or 11 drives) for data protection - resilvering time

[CJRoss]

I've been using an 11 drive raidz3 configuration for my main server for around a decade now with no problems. Pretty sure all of the drive replacements have been due to size, not any issues, but it's hard to remember over that long a time frame. I think I'm on my fourth expansion.

The resilvers are long, but IIRC still less than a day, even with all of the data I have stored on them. Right now I'm using about 50TB.

 

[ChrisRJ]

I must admit that I have only just now skimmed over this thread, because until now I had managed to miss it.

While I concede that I may very well have missed that, it seems to me that a certain part of this discussion falls into the bucket "penny-wise and pound-foolish". To be more specific:

• Discussing from how many vendors one should source HDDs, is more or less premature before there is a standby server in a separate location with a semi-real-time replication (think in the direction of Oracle GoldenGate).
• The same goes for a really solid and regularly tested backup.
• What about power distribution etc.?

I am not saying that the points brought up are wrong. But I disagree with the priority. Because, at least under normal circumstances, the whole exercise is about business-continuity. And HA of a single system (esp. if it is custom- or even home-built) is usually not a good approach to achieve this. Unless we are talking really serious money. But then you can often get this way cheaper than by reaching for "7 nines" in availability.

My $0.02

 

[Ericloewe]

Yeah, micro-optimizing things yields, at best, small results. Use your time to design and test a backup strategy.

 

[wojciech]

Thanks for all the replies! One follow-up question:
When creating a new vdev, is it SAFE to "force" and go ahead despite the message "Mixing disks of different sizes in a VDEV is not allowed"?
I have 8 x 10 TB + 3 x 14 TB drives and want to create a single 11-drive vdev.
I know that those 14 TB drives will only be used as 10 TB, but that's OK.
I'd just like to make sure that I won't lose the entire vdev (or something similar) by mixing drive sizes."

 

[Ericloewe]

Yes, your understanding is correct.