Proxmox with iSCSI Equallogic SAN

Jun 28, 2019
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Hi,

I've setup a environment with proxmox 6 and iSCSI Equallogic (DELL), this kind of storage requires some TCP modifications to work correctly with multipath..

One feature that is necessary for this storage to improve iscsi performance is "Disable DelayACKs" on Hosts connected to the storage..

I can't find on Proxmox where can I disable delay_acks on Linux ( /proc/sys/net/ipv4/tcp_quickack ) or ( /proc/sys/net/ipv4/tcp_nodelay) ...

Without this we're seeing a lot of "TCP retransmissions" on the storage center from proxmox hosts...

How can I disable delays acks on proxmox iscsi interface nics?
 
Jun 28, 2019
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Yep.. I know.. but I coud not find it anywhere thought linux/debian...

I'm trying to make it work right now using iscsi offload from my broadcom nic (57810).. using software iscsi (open-iscsi) I think it's not possible to disable delay ack.
 

menk

Active Member
Apr 3, 2014
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Italy - Forlì
Hi Danilo, but you have only "tcp retrasmissions" message, or you have other problem? Like slow performance or other????
 
Jun 28, 2019
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We are observing only tcp retransmission.. above 5% in some periods.. but it was higher when the interface MTU was in 9000 .. We lowered the mtu to 1500 it dropped the tcp retransmission a little bit.. but not 100%... I'm also searching why the MTU is also causing high tcp retransmission... my entire hardware infrastructure already works great with MTU 9000 and ESXi (with delayack off).. the problem only start to happen after Proxmox deployment..
 
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