On Fri, Sep 25, 2009 at 9:57 PM, FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx> wrote: > On Fri, 25 Sep 2009 14:39:59 +1000 > ronnie sahlberg <ronniesahlberg@xxxxxxxxx> wrote: > >> You might find this tool useful. >> I recently added very simple iscsi support to DBENCH ( http://dbench.samba.org ) >> so that dbench has a minimal iscsi initiator built in. >> >> This is sometimes useful since it allows to bypass any iscsi initiator >> layer, like open-iscsi, on the host and to get full control of exactly >> what commands will be issued to the target and accurate measures since >> one can know that the data was served across the network and not from >> a local cache. > > Sounds interesting but you need to put the iscsi initiator feature > into dbench? > > I mean that if dbench issues SCSI commands via sg from a load file, > can you can achieve similar things? In theory yes. In practice no. I could never reach very high workloads using the sg interface but using the iscsi backend to dbench I could easily generate 100s of thousands of i/o per second. I guess the queueing and i/o scheduling of the kernel comes in the way and interferes. Using a tiny initiator built into dbench I avoid all interference from the kernel. (dbench can also generate I/O directly to a sd device) > > > btw, I got the latest code from the git tree, but seems that there is > no iscsi support yet. > Oh, sorry about that. the webpage had a regression. The correct git tree is : git+ssh://git.samba.org/data/git/sahlberg/dbench.git Please try this tree. -- To unsubscribe from this list: send the line "unsubscribe stgt" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
