On Wed, Jan 19, 2011 at 10:21 PM, Wolfgang Denk <wd@xxxxxxx> wrote: > Dear =?ISO-8859-15?Q?Stefan_/*St0fF*/_H=FCbner?=, > > In message <4D361F26.3060507@xxxxxxxxxxxxxxxxxx> you wrote: >> >> [in German:] Schätzelein, Dein Problem sind die Platten, nicht der >> Controller. >> >> [in English:] Dude, the disks are your bottleneck. > ... > > Maybe we can stop speculations about what might be the cause of the > problems in some setup I do NOT intend to use, and rather discuss the > questions I asked. > >> > I will have 4 x 1 TB disks for this setup. >> > >> > The plan is to build a RAID0 from the 4 devices, create a physical >> > volume and a volume group on the resulting /dev/md?, then create 2 or >> > 3 logical volumes that will be used as XFS file systems. > > Clarrification: I'll run /dev/md* on the raw disks, without any > partitions on them. > >> > My goal is to optimize for maximum number of I/O operations per >> > second. ... >> > >> > Is this a reasonable approach for such a task? >> > >> > Should I do anything different to acchive maximum performance? >> > >> > What are the tunables in this setup? [It seems the usual recipies are >> > more oriented in maximizing the data troughput for large, mostly >> > sequential accesses - I figure that things like increasing read-ahead >> > etc. will not help me much here?] > > So can anybody help answering these questions: > > - are there any special options when creating the RAID0 to make it > perform faster for such a use case? > - are there other tunables, any special MD / LVM / file system / > read ahead / buffer cache / ... parameters to look for? XFS is known for it's slow speed on metadata operations like updating file attributes/removing files..but things gonna change after 2.6.35 where delaylog is used. Citating Dave Chinner : < dchinner> Indeed, the biggest concurrency limitation has traditionally been the transaction commit/journalling code, but that's a lot more scalable now with delayed logging.... So, you may need to benchmark fs part. > > Thanks. > > Wolfgang Denk > > -- > DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel > HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany > Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd@xxxxxxx > Boykottiert Microsoft - Kauft Eure Fenster bei OBI! > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- Best regards, [COOLCOLD-RIPN] -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
