DRBD To Be Included In Linux Kernel 2.6.33 166
An anonymous reader writes "The long-time Linux kernel module for block replication over TCP, DRBD, has been accepted as part of the main Linux kernel. Amid much fanfare and some slight controversy, Linus has pulled the DRBD source into the 2.6.33 tree, expected to release February, 2010. DRBD has existed as open source and been available in major distros for 10 years, but lived outside the main kernel tree in the hands of LINBIT, based in Vienna. Being accepted into the main kernel tree means better cooperation and wider user accessibility to HA data replication."
Re:How does this differ from NBD? (Score:5, Informative)
The "DR" stands for Distributed and Replicated. DRBD is way higher-level in function, but integrated lower-level than the simple userspace daemon that the server side of NBD uses.
Read the docs, the differences should be blindingly obvious.
Re:Another networking module... great (Score:5, Informative)
You want "make localmodconfig", which I think was also added recently, possibly to 2.6.32 actually. This builds a kernel using a local .config file, except that it only compiles modules that show up in lsmod. So if you boot off your vendor kernel with a squillion modules, let it load the modules you actually *use* then do make localmodconfig, you can make a kernel that only contains those modules. I don't know what it does if module names etc change, maybe you'd need manual fixup then - should still be less work than you currently are doing though.
There's some explanation here, though it might be for an out-of-date version of the patch:
http://linux.derkeiler.com/Mailing-Lists/Kernel/2009-09/msg04230.html [derkeiler.com]
As the other reply said, make oldconfig is also useful to important settings from a previously configured kernel, can save a lot of time.
Re:How does this differ from NBD? (Score:4, Informative)
Another way of putting (some configurations of) DRBD is probably "Networked block device RAID, but more flexible".
Re:Another networking module... great (Score:5, Informative)
i'm sorry to say, but that's not a good attitude. and i'm being polite here.
developers need testers. some arrogant assholes might claim they don't, but then they're known as ones. now, to attract testers you not only are polite to them, you also do not discourage them by breaking or ignoring things that hamper them (but might not concern casual users), you actually should build tools and other support functionality for testing.
essentially, having less testers will impact quality of the software for everybody else, so casual users also should desire for the project to have more testers.
i'm glad that at least some kernel hackers recognise this, and 2.6.32 actually has support for new configuration method, which looks at already loaded modules and some other stuff to create trimmed down kernel config - http://kernelnewbies.org/LinuxChanges#head-11f54cdac41ad6150ef817fd68597554d9d05a5f [kernelnewbies.org]
Re:2002 (Score:1, Informative)
uhm. just read that link and yeah, 2002. it reads like linux-ha circa 2002 /w pre-v8 DRBD + heartbeat v1. HA concepts are similar across the board but HA on linux has come a long way in the last 5 years or so. if youve already written DRBD off as inferior at least check out www.clusterlabs.org and see where the CRM/failover software side of linux HA is at these days. its quite impressive and compliments DRBD perfectly as a rock-solid FOSS HA solution.
Compared to VMS clusters... (Score:3, Informative)
Ah, Linux gets disk level clustering?
It is interesting to compare with what VMS offered 25 years ago [wikipedia.org]:
- VMS could have multiple nodes (can DRBD? It is not obvious from the web site.)
- All VMS nodes have read and write access to the file systems
- The distributed lock manager [wikipedia.org] helps with file locking in this case.
- VMS has the concept of quorum [hp.com] to avoid the "split brain" syndrom mentioned on the web page.
Re:Another networking module... great (Score:2, Informative)
What’s wrong with simply using “make oldconfig”?
Re:2002 (Score:1, Informative)
Yeah, that one is very old. It's a very different ballgame now with FreeBSD as well. We can still stack the vblock devices as we like, as many as we like. But now it's possible to do more, a lot more. GGate s exceptionally good now, a lot has happend in six years.
Personally I prefer ZFS at the bottom, with encrypted network replication to the HA nodes.