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Re: [Moosefs-users] Chunks
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From: Michal B. <mic...@ge...> - 2011-03-03 09:05:46
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Hi! Do you mean why we chose ext3 for the chunkservers? When we started building our infrastructure ext4 was even not available then. Regards Michal -----Original Message----- From: Steve [mailto:st...@bo...] Sent: Wednesday, March 02, 2011 6:31 PM To: Heiko Schröter Cc: moo...@li... Subject: Re: [Moosefs-users] Chunks What is the feature in moosefs that makes you choose it over say ext4 ? I'm not understanding this yet! -------Original Message------- From: Michal Borychowski Date: 02/03/2011 16:08:20 To: 'Heiko Schröter' Cc: 'moosefs-users' Subject: Re: [Moosefs-users] Chunks Hi Heiko! We undestand your point and can see that using RAID6 + goal=1 is a little bit more economical than RAW HDD + goal=2 but this is not a huge difference as you still need some disks for the RAID6. The main purpose of MooseFS system is security not the space savings. And solution with RAID6 is not that secure. We generally advise not to use any RAIDs and using at least goal=2. Module responsible for rebalancing chunks operates on chunks (independently of the files). Each chunk is treated individually while making different operations. So the requested change is not just a matter of providing a simple patch, it would be a change in the "philosophy" of the system and unfortunately won't be possible. Kind regards Michal -----Original Message----- From: Heiko Schröter [mailto:sch...@iu...] Sent: Monday, February 28, 2011 4:13 PM To: mic...@ge... Subject: Chunks Hi Michael, sorry for seeing your post to the list too late before posting my screenshots. I can see your point, but to us it would be very important to have a "chunkabilty" or striping in other fs of one. The reason: We receive a lot of large satellite data files per day. (400MB to 2GB per file). The storage space is limited (because of the governmental funding), so we need to keep risks to a certain minimum with the ressources given. We are running Hardware raid6 on our chunkservers. So there is some safety margin here. But we need to make sure that in case of a total breakdown of a chunkserver only some files are lost to 100%, and not all files beeing damaged to a certain extend and therefore irrecoverable. So if I could be of any help testing a patch I would very much appreciate it. Thanks for your time looking into this. Regards Heiko Hi Heiko! You are definitely right! I made a mistake writing all chunks of the file with goal=1 would reside just on one chunkserver. Each chunk of the file would go (more or less by random) to different chunkservers. On the other hand we again focus on the point that using goal=1 is almost useless. Unless these are some temporary, unimportant files. The expectation of distributed file system is to keep at least two copies of the file :) Thank you for being conscious :) ---------------------------------------------------------------------------- - Free Software Download: Index, Search & Analyze Logs and other IT data in Real-Time with Splunk. Collect, index and harness all the fast moving IT data generated by your applications, servers and devices whether physical, virtual or in the cloud. Deliver compliance at lower cost and gain new business insights. http://p.sf.net/sfu/splunk-dev2dev _______________________________________________ moosefs-users mailing list moo...@li... https://lists.sourceforge.net/lists/listinfo/moosefs-users ---------------------------------------------------------------------------- -- Free Software Download: Index, Search & Analyze Logs and other IT data in Real-Time with Splunk. Collect, index and harness all the fast moving IT data generated by your applications, servers and devices whether physical, virtual or in the cloud. Deliver compliance at lower cost and gain new business insights. http://p.sf.net/sfu/splunk-dev2dev _______________________________________________ moosefs-users mailing list moo...@li... https://lists.sourceforge.net/lists/listinfo/moosefs-users |
