From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans Reiser Subject: Re: Corrupted/unreadable journal: reiser vs. ext3 Date: Wed, 12 Feb 2003 15:42:34 +0300 Message-ID: <3E4A413A.9090609@namesys.com> References: <93F527C91A6ED411AFE10050040665D0049C06D5@corpusmx1.us.dg.com> <3E4A266E.2A258472@interface-ag.com> <3E4A28F8.2030506@namesys.com> <3E4A35E9.1585BB5@interface-ag.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: list-help: list-unsubscribe: list-post: Errors-To: flx@namesys.com In-Reply-To: <3E4A35E9.1585BB5@interface-ag.com> List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Dirk Schenkewitz Cc: Reiserfs List , Jeff Mahoney , grev@namesys.com Dirk Schenkewitz wrote: >Hi Hans, > >Hans Reiser schrieb: > > >>Dirk Schenkewitz wrote: >> >> >> >>>Wayne, >>> >>>berthiaume_wayne@emc.com schrieb: >>> >>> >>> >>> >>>> Dirk, I'd be interested in hearing from you your performance >>>>experience with ext3 when it reaches 96% full. >>>> >>>> >>>> >>>> >>>Well (*shrug*), there seems to be nothing special about it. I did >>>not do any timing test when such a fileysytem went full. In fact, >>>becoming 100% full is not "mormal", it happens when I put stuff >>>on it just to have it out of the way for some time. The filesystem >>>is then used as some kind of "storage cellar". >>> >>>Aside from that - speed becomes noticeable (I believe, at least) >>>when using 'xv' on a directory with lots of pictures, say, between >>>2000 and 3000, and the thumbnails are loaded during the first access. >>>This takes more than a minute (estimated, I did not look at the >>>clock). >>> >>>Another thing is when 'xv' creates the thumbnails. A few times it >>>happened that a filesystem which was rather full ran out of space >>>when creating the thumbnails. (That's not critical, all you "loose" >>>are some of the thumbnails, which can be recreated any time later.) >>>But I don't know how/when 'xv' stores the thumbnails, I only know >>>that they are kept in memory as long as they are in use. Then linux >>>itself does some buffering, so only the first access on a directory >>>can make a testimony. That said, I can can only talk of my subjec- >>>tive impressions, and I have not noticed any slowdown until there >>>are 0 bytes left. But it is hard to tell, because the difference >>>between 96% and 100% are only 320 MB on a 8 GB partition, and that >>>space fills up rather fast. >>> >>>While you ask - what are the "amounts" of slowdown if a reiserfs >>>gets more than 96% full? >>>- Less than 4% percent? (I might not notice that.) >>>- between 4% and 8%? (I might notice, but I can live with that >>> easily. Then again, ext3 doesn't seem to have such problems.) >>>- more than 8%, maybe much more? (That might become annoying. >>> In that case I believe that ext3 is better for my purposes.) >>> >>>You see, I'm not an expert, I'm "just using filesystems". Please >>>take the mentioned percentages as guesses - depending on the >>>situation, I might not even notice 10% slowdown... >>> >>>Hope that answers your question - does it? >>> >>>Happy coding >>> dirk >>> >>> >>> >>> >>and if you can fit more data onto reiserfs partitions than onto >>ext3 partitions? >> >> > >That's what I'm looking for! > > > >>Is it a fair comparison to compare at equal percents full? >> >> > >Considered that way: No. Comparison should be between absolute >bytes I can put on a reiser-filesystem against an ext3-filesystem >while the partition sizes are equal. Hm. Please excuse me if this >is a FAQ: Can you give me a hint where to find such a comparison? >To put it in other words: How much more bytes can I put on a >reiser-fs compared to an ext3-fs when the partition sizes are >equal? > That depends on your file size distribution, and on whether you use the tails mount option. Probably ~10% more. Forgive me, it has been a while since it was measured. Elena, can you copy the kernel source code onto a partition until it fills up, make it a large partition please, and compare ext3 to reiserfs V3/V4? >But even then: If I have more space available, I will happily >use it, so even if I can put 500 MB more on it, I will manage >to fill it up - what will happen then? > I am not answering this because jeff improved things a lot, and I don't know how good/bad they are currently.... > >Thanks for reading & answering (also in advance :-)) > dirk > > > -- Hans