Ubuntu iSCSI compatibility problem.

recently, I had build a NAS storage to connect vSphere ESXi Hypervisor.


so far, I suffered so many trial and error.


Generally, Ubuntu has good system stability and compatibility.

but some part is not. especially at storage area.


iSCSI and NAS is basic protocols at storage area network.

but Ubuntu has some bugs.


Ubuntu 14.04 and ietd(iSCSI daemon) or nfs-kernel-server(NFS daemon) is not show good compatibility.

(of course Ubuntu 14.04.1 solved this problem for NFS.)


Most of all, Speed is not satisfied me. especially at using  iSCSI.

even I tuned Jumbo frame and added better performance 1Gbit NICs.

but at sequential write, 20~30MB/s speed was slow down than previous version.

Ubuntu 12.04 version was show better performance.

I think it's not just 3.14 kernel's characteristic.

at same disk volume, iSCSI speed 20~30MB/s but, NFS speed 60~80MB/s.

I couldn't understand why this outcomes occured.

so I changed iSCSI initiator from ESXi to Windows.

after changing, I watched unbelievable outcome. 70~80MB/s speed.

in this case, you may think, "It's ESXi's problem. not Ubuntu."

but I 'm not think so. there are many storage vendor using iSCSI target server daemon(ietd).

they don't suffer same problem like me. and most of them use CentOS as base system.

in my opinion, Ubuntu don't care compatibility with iSCSI target daemon.


If Ubuntu dev team consider cloud storage system as future step, SAN protocol tuning must will be most important aim.

MS released Windows Storage Server edition and provide their software to various server vendors.

It's big threats for Ubuntu. I want that Ubuntu not just stay Openstack project.


Regards.