Multiple Fibre Channel Ports
by Chris Dos
Is there a way to to use multiple fibre channel ports for the same target? Is
that I'm thinking of called Asymmetric Logical Unit Access (ALUA)?
I have a couple of dozen clients connecting to the same FC LUN. They are
sharing the LUN using Tiger Store acting as the master. I'm currently
saturating a single 8Gb FC connection. I've purchased a quad port 8Gb card
and I'd like set it it up so all the clients will go through all four ports.
Perhaps something like round robin that I read about online.
Can I just share the same target out the other ports and add the same ACLs?
I've been searching but have not found anything yet on a configuration like this.
Chris
5 years, 1 month
FileIO Backstore and write_back
by Chris Dos
Is the write_back option the same as the buffered option mentioned here:
http://linux-iscsi.org/wiki/LIO
It says the buffered option is unsafe and not to use it.
I created a 10TB file as a test LUN yesterday on a ZFS dataset and I enabled
write_cache and emulate_write_cache=1. Performance was staggeringly good
compared to using a ZVOL. The target LUN is shared to multiple initiators
using Tiger Store software and it is formatted with NTFS.
Does write_back and emulate_write_cache do the same thing?
I'm going to moving to using a file instead of a ZVOL for production. I'm
want to set this up safely though and to be able to recover from a kernel
crash or something similar. The servers are on UPS and they are all using ECC
memory. I don't mind that having to do a NTFS disk check if something
unforeseen happens, but having a whole corrupted LUN is not acceptable.
Any advice would be greatly appreciated.
Chris
5 years, 1 month
MaxConnections=1 iSCSi default
by Rob Townley
I noticed that MaxConnections=1 is a default, but have not found solid
documentation on what this parameter actually does.
What does MaxConnections do?
Is it reasonable to assume that increasing MaxConnections to 4 | 8 | 16
will increase performance safely?
5 years, 1 month
ZFS ZVOL and emulate_write_cache
by Chris Dos
I'm trying to set the emulate_write_cache=1 on a block ZFS ZVOL.
Targetcli throws an error:
Cannot set attribute emulate_write_cache: [Errno 22] Invalid argument
Dmesg says:
emulate_write_cache not supported for this device
Based on what I've been reading, shouldn't this work?
Chris
5 years, 1 month
