Question for our dealers or more technical Kaleidescape gurus:
Back in the 5U days, before there were hot-spare drives, I understood the basics of drive-size mixing: add anything less than three of a larger size drive and you won't yet get the benefit of the extra space given the RAID redundancy allocation; they'll appear as if they're the smallest-size drives until there's enough of them installed.
However, I'm not quire sure how the system manages this process with the hot-spare.
I have a 3U server with 6 2TB drives, 7 empty slots, then a 7th 2TB drive that's the hot spare (blinking blue light).
Question is this: If I now add TWO 3TB drives, what happens to the hot-spare (currently a 2TB)? Does the system now realize that one of the two new larger 3TB drives should become the hot-spare, convert the old hot-spare into a working disk, and therefore I'll end up with 7 "in-use" 2TB drives, a single in-use 3TB drive (acting as a 2TB), and a new 3TB hot-spare? I'd then need to add at least TWO more 3TBs to start getting more than 2TB of usable space on the new drives?
If this is the case, the old rule of thumb that you need to add THREE drives of a larger size before you gain any real advantage for the larger drives, should really be FOUR drives, since one will have to become the new hot spare. Yes?
Maybe this is an easier way to ask the question: Does the system automatically "take" one of whatever is the largest drive size installed and make that the hot-spare, removing it from storing any actual content?
Does that make sense?
Back in the 5U days, before there were hot-spare drives, I understood the basics of drive-size mixing: add anything less than three of a larger size drive and you won't yet get the benefit of the extra space given the RAID redundancy allocation; they'll appear as if they're the smallest-size drives until there's enough of them installed.
However, I'm not quire sure how the system manages this process with the hot-spare.
I have a 3U server with 6 2TB drives, 7 empty slots, then a 7th 2TB drive that's the hot spare (blinking blue light).
Question is this: If I now add TWO 3TB drives, what happens to the hot-spare (currently a 2TB)? Does the system now realize that one of the two new larger 3TB drives should become the hot-spare, convert the old hot-spare into a working disk, and therefore I'll end up with 7 "in-use" 2TB drives, a single in-use 3TB drive (acting as a 2TB), and a new 3TB hot-spare? I'd then need to add at least TWO more 3TBs to start getting more than 2TB of usable space on the new drives?
If this is the case, the old rule of thumb that you need to add THREE drives of a larger size before you gain any real advantage for the larger drives, should really be FOUR drives, since one will have to become the new hot spare. Yes?
Maybe this is an easier way to ask the question: Does the system automatically "take" one of whatever is the largest drive size installed and make that the hot-spare, removing it from storing any actual content?
Does that make sense?
Last edited: