[Novalug] benchmarks and iSCSI

[Miguel Gonzalez Castaños]

John Franklin escribió:
> 1900MB/s?  How are you connecting the iSCSI drive?  100Base-T tops out 
> at 12MB/s, GigE could do about 100-120MB/s (reality: less). 10GigE 
> will get you (best, utopian case) 1000-1200MB/s.  How are you getting 
> 1900MB/s?  It sounds like you've got some significant caching on the 
> client side polluting your results.
>
> 34MB/s reads sounds like what you should be seeing over GigE, 
> untuned.  You should be able to boost it some with Jumbo frames, 
> sysctl net.* tuning and some NIC interrupt tuning.  Also, change the 
> block size to 1MB.  IIRC, VMFS3 uses 1MB blocks.
I'm using Gigabit and of course there should be some sort of caching.

I know about jumbo frames but can you point me to any documentation of 
how to tune sysctl settings and some NIC interrupts?

When you are talking about the block size to 1 MB, what you are talking 
about? The dd test? the filesystem?

Finally, I'm using VMware. Some people say that the best setting is 
using iSCSI under Windows and save the virtual hard drives in the NTFS 
filesystem. I'm trying to compare this configuration with real iSCSI to 
see what is better. (I have Vmware with Windows as a host OS but I'm 
using Debian as a guest).

Thanks!

Miguel