Re: Can "mdadm" linux RAID go large?
From: Dan Stromberg <hidden>
Date: 2005-06-07 23:53:38
On Tue, 2005-06-07 at 16:46 -0700, Mike Hardy wrote:
Not sure about the size limits per se (http://www.suse.de/~aj/linux_lfs.html has good info there)
Thanks for the link.
I can say that with a very large number of disks, you will hit single-block read errors quite frequently due to the nature of the math behind MTBF. This will lead to frequent drive expulsion / rebuild cycles, as discussed in another thread today.
Say with 210 SATA's, for example? Would I be replacing disks every day or something?
In another question (you could post them all as one mail, incidentally...)
True, but I've been hypothesizing that sometimes folks are reluctant to: 1) Wade all the way through a long series of questions 2) Respond to a message if they don't have the answers to all questions
you asked if it was stable. The only evidence appears to be anecdotal, but it appears extremely stable to me, even under very heavy testing - normal new machine cpu/network/ram burn-in tests, combined with multiple bonnie++ processes hitting the array. Any problems I've had have been attributable to hardware or hardware drivers thus far.
Good to know.
There have been problems (like the recent set of looping-resync issues for instance), but I don't remember hearing any that resulted in data loss, and they get fixed quickly. Serious problems still leave you with your data on a set of disks in a known format, which means that it may be laborious but you can reconstruct. So it "degrades" more gracefully than the black box that are some hardware raid systems.
OK.
It takes care to run well and safely though, as with any machine.
Yes, I'm expecting that. Thanks!