On Thu, 31 May 2007, Richard Scobie wrote: > Jon Nelson wrote: > > > I am getting 70-80MB/s read rates as reported via dstat, and 60-80MB/s as > > reported by dd. What I don't understand is why just one disk is being used > > here, instead of two or more. I tried different versions of metadata, and > > using a bitmap makes no difference. I created the array with (allowing for > > variations of bitmap and metadata version): > > This is normal for md RAID1. What you should find is that for > concurrent reads, each read will be serviced by a different disk, > until no. of reads = no. of drives. Alright. To clarify, let's assume some process (like a single-threaded webserver) using a raid1 to store content (who knows why, let's just say it is), and also assume that the I/O load is 100% reads. Given that the server does not fork (or create a thread) for each request, does that mean that every single web request is essentially serviced from one disk, always? What mechanism determines which disk actually services the request? -- Jon Nelson <jnelson-linux-raid@xxxxxxxxxxx> - 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
