Oh, thanks, that does not sound very encouraging. In our case it looked the same, we had to reboot three ESXi nodes via IPMI, because it got stuck at ordinary soft reboot.
1. RecoveryTimeout is set at 25 on our nodes 2. We have one two-port adapter per node (Connect-X 5) and 4 iSCSI GWs total, one per OSD server. Multipath works, tested it by randomly rebooting one of two switches or manually shutting down the port. One curious thing I did not mention before is that we see a number of dropped Rx packets on each NIC that corresponds to the iSCSI VLAN. Increase in the dropped packets seems to correlate with the current IOPS load.
I am beginning to settle with the version that our cluster is quite low on IOPS generally and slight increase in traffic may significantly raise latency on the iSCSI target. And ESXi is just being very touchy about that.
On 4 Oct 2020, at 18:59, Phil Regnauld < pr@xxxxx> wrote:
Yep, and we're still experiencing it every few months. One (and only one) ofour ESXi nodes, which are otherwise identical, is experiencing total freezeof all I/O, and it won't recover - I mean, ESXi is so dead, we have to go intoIPMI and reset the box...We're using Croit's software, but the issue doesn't seem to be with CEPH somuch as with vmware.That said, there's a couple of things you should be looking at:1. Make sure you remember to set the RecoveryTimeout to 25 ?https://docs.ceph.com/en/latest/rbd/iscsi-initiator-esx/2. Make sure you have got working multipath across more than 1 adapter.What's possibly biting us right now, is that with 2 iscsi gateways in ourcluster, and although both are autodiscovered at iscsi configuration time,we see that the ESXi nodes still only will show one path to each LUN.Currently these ESXi nodes have only 1 x 10gbit connected, it looks likeI'll need to wire up the second connector and set up a second path tothe iscsi gateway from that. It may not solve the problem, but it mightlower the I/O on a single gateway enough that we won't see the problemanymore (and hopefully our customers stop getting pissed off).Cheers,PhilGolasowski Martin (martin.golasowski) writes:For clarity, the issue has been reported also before:
https://www.spinics.net/lists/ceph-users/msg59798.html <https://www.spinics.net/lists/ceph-users/msg59798.html>
https://www.spinics.net/lists/target-devel/msg10469.html
On 4 Oct 2020, at 16:46, Steve Thompson <smt@xxxxxxxxxxxx> wrote:
On Sun, 4 Oct 2020, Martin Verges wrote:
Does that mean that occasional iSCSI path drop-outs are somewhat
expected?
Not that I'm aware of, but I have no HDD based ISCSI cluster at hand to
check. Sorry.
I use iscsi extensively, but for ZFS and not ceph. Path drop-outs are not common; indeed, so far as I am aware, I have never had one. CentOS 7.8.
Steve
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