On Wed, Aug 29, 2012 at 8:13 PM, Jonathan Tripathy <jonnyt@xxxxxxxxxxx> wrote: > On 30/08/2012 01:09, Jonathan Tripathy wrote: >> >> Hi Everyone, >> >> I'm using bcache with a RAID1 pair of SSDs (for the cache) with a >> MD-RAID10 spindle array for the backing device. On top of this is LVM. This >> setup is used with the Xen Hypervisor. Bcache is formatted with a sector >> size of 512 bytes. >> >> If I use an LV for a Linux DomU, I get fantastic disk performance using >> fio (about 23k random write). However, when I use IOMeter in a Windows HVM >> DomU (with GPLPV drivers installed), my avg IOPS is around 4000. I am using >> the "default" Access Specification. Am I doing something wrong? Changing the >> number of workers doesn't seem to help. >> >> Any advice is appreciated. >> >> Thanks >> > Actually nvm, I forgot to enable the dist target for each of the works. Now > I'm getting an avg iops of about 34k. > > But this does leave me with a question: is the number of "workers" in > IOMeter akin to "IO Depth" in fio? I've not used IOmeter, but I would assume that the number of "workers" would be similar to the number of "jobs" in fio. IO depth/queue depth is the number of IO requests that are queued for processing at any one time. So, if you've got 4 workers, each keeping one IO operation queued at all times, your effective IO depth would be 4, while the IO depth for each job/worker would be 1. That's my understanding at least. -davidc -- To unsubscribe from this list: send the line "unsubscribe linux-bcache" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
