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ewwhite / zfs-ha

ZFS High-Availability NAS
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Why not use iSCSI instead of SAS? #39

Closed snaix closed 2 years ago

snaix commented 2 years ago

Hi @ewwhite

The zfs-ha is cool. After reading the wiki, I have an idea about replacing SAS cable with ethernet cable, and use a iSCSI disk over LAN.

look at this image: image

If just replace SAS cable with ethernet cable, it seems everything is fine, they have same logic: just replace a cable type, nothing changed on ZFS. Of course, with iSCSI, there are more coupling, like NIC, Cable, Switch, and TCP congestion problem. But blocks transmission over Ethernet provides more flexibility: we can use any server to be a ZFS head node, when the old one was crashed. And also, we can use an independent switch (and iscsi multi-path) for storage to avoid switch SPOF, congestion problem...

The performance problem doesn't seem serious at present: 10/25/100GE is more and more popular, faster than SAS3 12G. And iSER...

So is there any problem with this idea?

ewwhite commented 2 years ago

Hello,

This is definitely something you can explore. It's out of scope for this project, though.