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What is the advantage of "network raid-1" over raid-1? It seems to me that block replication is best left below the OS.
by delano 19y ago
What is the advantage of "network raid-1" over raid-1? It seems to me that block replication is best left below the OS.
- wmf 19y agoSome people don't want to pay for dual-controller hardware RAID, so DRBD is the software equivalent.
- rcoder 19y agoThe description of DRBD as software RAID is a bit misleading, since in most deployment scenarios, only the "primary" node of the pair can actually write data to the replicated volume. It's real use is in building high-availability services -- since the "mirrored" disks aren't in the same box, you can have an up-to-the-second copy of the data there. The two systems don't even have to be in the rack next to each other, which is a tough trick to pull off with normal hardware RAID. As I said in my other comment, though, it is a lot slower than native disk writes.
- rcoder 19y agoLet me ask you the following re-factored version of your question and see if it illustrates the value of DRBD: > What is the advantage of "network I/O" over I/O? It seems to me that file copying is best left below the OS. Basically, DRBD gives you RAID-like replication of data across multiple physical hosts. This makes deployment of high-availability services stupidly easy, if sometimes less efficient than applicaiton-level replication protocols. For mail spools, NFS shares, or other simple file-based systems, though, it works pretty well.