Am Dienstag, 13. Februar 2007 00:31 schrieben Sie: > Martin A. Fink wrote: > > I have to store big amounts of data coming from 2 digital cameras to disk. > > Thus I have to write blocks of around 1 MB at 30 to 50 frames per second for > > a long period of time. So it is important for me that the harddisk drive is > > reliable in the sense of "if it is capable of 50 MB/s then it should operate > > at this speed. Constantly." > > The good old handful of suggestions: > > - Use a dedicated disc for the task.
I used a dedicated disk for this task. No one else besides the task is writing to it! > - Use an empty disc so there is no fragmentation. All tests were performed on empty disk! > - Buy a bigger disk, they have high bandwidths. I have a flash disk from a manufacturer who grants me 48 MB/s. And FreeBSD as well as Windows reach this value. Only Linux 2.6.18 is far away from it (42 MB/s) > - Buy a more "specialized" disc. see above > for e.x.: Western Digital Raptor X(*) a 150GB, 10-KRPM S-ATA disc. > - Buy several discs and use RAID 0 > or alternate between discs when writing. What I have to build is an application for the International Space Station ISS. I am limited with power and space. So If the disk is able to write constantly 48 MB/s then the Operating System should do this! > - use XFS. AFAIK XFS has about the best "large file" and "high > bandwidth" characteristics. > - that with XFS you can preallocate the files doesn't seem relevant in > this case. It's more for the case that you write several files > simultaneously over a longer period of time. > - Write to one large file and separate the individual files later. > > if you are sure that you don't get a power-failure: > - Disable Write-Barriers, especially on a logging-filesystem. > - Enable write-caching. > (hdparm doesn't appear to be able to do that with a SATA-disc, but > blktool appears to be able to) > The later has a good chance of corrupting your filesystem when you do > get a power-failure!!! > > > > *: > I don't think you want something from the server-line, > SCSI/FibreChannel/...? > IIRC i read a something about the first 100MB/s disc with in the 15-KRPM > league. Power consumption! See above. > > Bis denn > The problem is: FreeBSD is fast, but lacks of some special drivers. Linux has all drivers but access to harddisk is unpredictable and thus unreliable! What can I do?? > -- > Real Programmers consider "what you see is what you get" to be just as > bad a concept in Text Editors as it is in women. No, the Real Programmer > wants a "you asked for it, you got it" text editor -- complicated, > cryptic, powerful, unforgiving, dangerous. > > -- Dipl. Physiker Martin Anton Fink Max Planck Institute for extraterrestrial Physics Giessenbachstrasse 85741 Garching Germany Tel. +49-(0)89-30000-3645 Fax. +49-(0)89-30000-3569 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
