On Monday, May 4, 2020 2:50 AM, hitachi303 <gentoo-u...@konstantinhansen.de> wrote:
> Am 03.05.2020 um 23:46 schrieb Caveman Al Toraboran: > > > so, in summary: > > /------------------------------------------------\ > > | a 5-disk RAID10 is better than a 6-disk RAID10 | > > | ONLY IF your data is WORTH LESS than 3,524.3 | > > | bucks. | > > \------------------------------------------------/ > > any thoughts? i'm a newbie. i wonder how > > industry people think? > > Don't forget that having more drives increases the odds of a failing > drive. If you have infinite drives at any given moment infinite drives > will fail. Anyway I wouldn't know how to calculate this. by drive, you mean a spinning hard disk? i'm not sure how "infinite" helps here even theoretically. e.g. say that every year, 76% of disks fail. in the limit as the number of disks approaches infinity, then 76% of infinity is infinity. but, how is this useful? > Most people are limited by money and space. Even if this isn't your > problem you will always need an additional backup strategy. The hole > system can fail. > I run a system with 8 drives where two can fail and they can be hot > swoped. This is a closed source SAS which I really like except the part > being closed source. I don't even know what kind of raid is used. > > The only person I know who is running a really huge raid ( I guess 2000+ > drives) is comfortable with some spare drives. His raid did fail an can > fail. Data will be lost. Everything important has to be stored at a > secondary location. But they are using the raid to store data for some > days or weeks when a server is calculating stuff. If the raid fails they > have to restart the program for the calculation. thanks a lot. highly appreciate these tips about how others run their storage. however, i am not sure what is the takeaway from this. e.g. your closed-source NAS vs. a large RAID. they don't seem to be mutually exclusive to me (both might be on RAID). to me, a NAS is just a computer with RAID. no? > Facebook used to store data which is sometimes accessed on raids. Since > they use energy they stored data which is nearly never accessed on blue > ray disks. I don't know if they still do. Reading is very slow if a > mechanical arm first needs to fetch a specific blue ray out of hundreds > and put in a disk reader but it is very energy efficient. interesting.
