Hi, I'm going to replace a h/w based RAID system (3ware 9650SE) by a plain s/w RAID0, because the existing system appears to be seriously limited in terms of numbers of I/O operations per second. Our workload is mixed read / write (something between 80% read / 20% write and 50% / 50%), consisting of a very large number of usually very small files. There may be 20...50 millions of files, or more. 65% of the files are smaller than 4 kB; 80% are smaller than 8 kB; 90% are smaller than 16 kB; 98.4% are smaller than 64 kB. 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. My goal is to optimize for maximum number of I/O operations per second. [I am aware that using SSDs would be a nice thing, but that would be too expensive.] 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?] Thanks in advance. Best regards, 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 Quote from a recent meeting: "We are going to continue having these meetings everyday until I find out why no work is getting done." -- 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
