Add Route
I am using release 2.2.0. When ppp starts I get a warning Add! route failed: ff02::: errno: Operation not supported I am using the ppp.conf from the handbook for PPPoE. PPP is enabled in /etc/rc.conf/local. There is an /etc/resolv.conf file with a search line and two nameserver lines. I have tried add and add! default HISADDR. I am new to DragonFly (from FreeBSD) and any help would be appreciated.
Re: hammer: undelete and questions
Shouldn't you look for a file named like 'T_X_F_07x05.rar.part1', instead of 'T_X_F_07x05.part1.rar' then ? It was the same problem, i just redownloaded it. Petr
HAMMER and RAID 5
I was wondering if HAMMER will ever have network based RAID 5. After researching several file systems it seems HAMMER is probably the closest to achieve this problem and will make HAMMER a pioneer. Any thoughts or ideas? TIA
Re: HAMMER and RAID 5
On Tue, Mar 3, 2009 at 1:08 PM, Mag Gam magaw...@gmail.com wrote: I was wondering if HAMMER will ever have network based RAID 5. After researching several file systems it seems HAMMER is probably the closest to achieve this problem and will make HAMMER a pioneer. Intuitively I highly doubt network RAID5 is worth it. Even local disk RAID5 is unusable for many work loads. In contrast, check out some of the more flexible RAID10 modes available in Linux: http://en.wikipedia.org/wiki/Non-standard_RAID_levels#Linux_MD_RAID_10 You can get N/M effective space (N raw storage / M copies) with RAID0-like striping for all of it. It performs very well and certainly much better than the parity-based RAID5. Imagine how RAID5 would work with network devices: Read old data block from one server Read parity block from another server Generate new parity block Write data block to one server Write parity block to another server All with NO atomicity guarantees, so HAMMER would have to pick up the slack. Even in the best case you have 8x the latency of a single trip to a machine (4 request/response pairs of 2 IOs each). All compared to a one round trip (2 IOs) to write to a plain slave, or N round trips for N redundant copies. What is an acceptable penalty on local disks is pretty heavy for network storage. If you really want, you can use vinum over iSCSI to get networked RAID5, but it will not perform well. -- Dmitri Nikulin Centre for Synchrotron Science Monash University Victoria 3800, Australia
1 week until Summer of Code application time
Here's a heads-up: Application time for organizations (not students) to get into the 2009 Summer of Code program is 1 week away. If you are any of these things: - potential student - potential mentor - person with an idea for a project Please mark it down at: http://www.dragonflybsd.org/gsoc2009/ It's OK to suggest an idea even if you don't have the time to mentor it. I do need more mentors names - remember, it gets you $500 in addition to helping the DragonFly project a great deal.
Can DFly root from a hammered-slice?
Hi all: I sliced my hard drive into ad4s1 and ad4s2, then disklable the former and create ufs on ad4s1a and hammer on ad4s2 The ad4s1a is mounted as /boot and ad4s2 as /, /usr and other staff are nullfsed to /pfs/... Then I edit the /boot/loader.conf with vfs.root.mountfrom=hammer:ad4s2 just as the rcconfig said. However, when I boot the box, it reports no disklabel and cannot boot. So, can DFly root from a slice not disklabel? Well, I know the disklabel is better, it is a mistake but I cannot bear a repartition now :( BTW, do we still need disklabel if we got gpt and hammer? best wishes whisper :)
Re: HAMMER and RAID 5
Dmitri Nikulin wrote: On Tue, Mar 3, 2009 at 1:08 PM, Mag Gam magaw...@gmail.com wrote: I was wondering if HAMMER will ever have network based RAID 5. After researching several file systems it seems HAMMER is probably the closest to achieve this problem and will make HAMMER a pioneer. Intuitively I highly doubt network RAID5 is worth it. Even local disk RAID5 is unusable for many work loads. In contrast, check out some of the more flexible RAID10 modes available in Linux: http://en.wikipedia.org/wiki/Non-standard_RAID_levels#Linux_MD_RAID_10 You can get N/M effective space (N raw storage / M copies) with RAID0-like striping for all of it. It performs very well and certainly much better than the parity-based RAID5. Imagine how RAID5 would work with network devices: Read old data block from one server Read parity block from another server Generate new parity block Write data block to one server Write parity block to another server All with NO atomicity guarantees, so HAMMER would have to pick up the slack. Even in the best case you have 8x the latency of a single trip to a machine (4 request/response pairs of 2 IOs each). All compared to a one round trip (2 IOs) to write to a plain slave, or N round trips for N redundant copies. What is an acceptable penalty on local disks is pretty heavy for network storage. If you really want, you can use vinum over iSCSI to get networked RAID5, but it will not perform well. Adding to that (as we have spent the past 12+ months researching all this..) - there IS prior art, and lots of it. [1] - none of it is fast - even over local 'Infiniband' - the most practical compromise seems to be deferred background replication to 'pools' that are themselves *hardware8 RAID5 (6 or 10). - 'hammer mirror-stream', especially if done over something faster than ssh, - eg: localy over 10GigE, iSCSI, or e-SAt over raw Ethernet, is a primo candidate for having at least one rapid-restoration near-real-time snapshot. But at the present state of the art, HAMMER is challenged w/r quotas, subvolume-only selective replication, and r/w mounting of the mirrored snapshot(s). Quite possibly there will be no 'one size fits all' solution, Too many compromises that pull in opposing directions. As has always been the case.. HTH, Bill [1] Start with the Wikipedia article on distributed file systems, paticularly replicated and fault-tolerant. Most are either IBM/Sun/Oracle/$AN-vendor, 'mainframe big-bucks' class, ELSE Linux whole-damn-world-in-the kernel wannabees. Among the contenders: - Gluster (problematic getting it to work with fuse on FreeBSD) - GFarm (wants to link in its own utils) - MooseFS (compiles sweetly on FreeBSD - but sparse docs) - Chiron (dirt-simple, but needs manual work if/as/when backends break) - Ceph (relies on btrfs - which is scary as the btrfs developers claim 'not ready yet..' Aside from Ceph, most of the others I mention use 'any POSIX fs' for eventual store. Chiron, to name one of many, expects those to be already-mounted smbfs or NFS mounts. AFAIK, 'POSIX' compatibility includes HAMMER fs, whether over sshfs sshftp, NFS, SMBFs, or ... so .. 'possibilites abound'. Speaking from the transpacific fiber private-network alpha test exposure, there ain't no magic to the network, though! What folks forget is that the delays introduced by each router or switch add up - even at 'light speed' to latency 'puters do not like. One can hope for paired electron technology but not 'soon' ;-)
