ISCSI TGT optimizing

Yesterday I did my first OMV install and it's looking good so far. I was even able to get ISCSI TGT up running on my first attempt. I also tried to install the zfs plugins but it failed on install for some reason and I didn't get the fault messages. So my ISCSI backing store ended up at raid 5 system /dev/md0 with an image on /mnt/iSCSI with no filesystem. In Windows, I formatted the filesystem in exFAT since I also like to access my iSCSI from my Mac. Would zfs make my iSCSI faster or are there other things I can do to make the system faster and/or safer? Can I for instance add CHAP authenticating by adding some extra options?

My system:

OMV 5.6.20-1 Usul

OMV running from a small spinning HDD (300GB)

i5 4670K @ 3400GHz, 16GB ram

At the time running 1Gb Lan but is waiting for my 10Gb equipment to arrive in some days.

Output of: omv-showkey tgt from my system:

<tgt>
<enable>1</enable>
<extraoptions></extraoptions>
<targets>
<target>
<uuid>26d3ad41-fd5f-4a67-997c-f27d4dffadd1</uuid>
<enable>1</enable>
<name>FilServ</name>
<iqn>iqn.2021-11.local.omv:filserv</iqn>
<backingstore>/dev/md0</backingstore>
<initiatoraddress>192.168.68.100 192.168.68.250</initiatoraddress>
<extraoptions></extraoptions>
</target>
</targets>
<images>
<image>
<uuid>1ed802ef-65d7-4443-8b33-70d50779ff65</uuid>
<path>/mnt/iscsi</path>
</image>
</images>
</tgt>

A thankful OMV and iSCSI user

Quote from chente

What exactly went wrong? ZFS menu not showing in storage section in GUI?

I'm not exactly sure what went wrong, but I did find this in my apt logs:

Configure zfsutils-linux (2.0.3-9~bpo10+1) ...
modprobe: FATAL: Module zfs not found in directory /lib/modules/5.10.0-0.bpo.8-amd64
Created symlink /etc/systemd/system/zfs-import.target.wants/zfs-import-cache.service  ^f^r /lib/systemd/system/zfs-import-cache.service.
Created symlink /etc/systemd/system/zfs.target.wants/zfs-import.target  ^f^r /lib/systemd/system/zfs-import.target.
Created symlink /etc/systemd/system/zfs-mount.service.wants/zfs-load-module.service  ^f^r /lib/systemd/system/zfs-load-module.service.
Created symlink /etc/systemd/system/zfs.target.wants/zfs-load-module.service  ^f^r /lib/systemd/system/zfs-load-module.service.
Created symlink /etc/systemd/system/zfs.target.wants/zfs-mount.service  ^f^r /lib/systemd/system/zfs-mount.service.
Created symlink /etc/systemd/system/zfs.target.wants/zfs-share.service  ^f^r /lib/systemd/system/zfs-share.service.
Created symlink /etc/systemd/system/zfs-volumes.target.wants/zfs-volume-wait.service  ^f^r /lib/systemd/system/zfs-volume-wait.service.
Created symlink /etc/systemd/system/zfs.target.wants/zfs-volumes.target  ^f^r /lib/systemd/system/zfs-volumes.target.
Created symlink /etc/systemd/system/multi-user.target.wants/zfs.target  ^f^r /lib/systemd/system/zfs.target.
zfs-import-scan.service is a disabled or a static unit, not starting it.
Job for zfs-load-module.service failed because the control process exited with error code.
See "systemctl status zfs-load-module.service" and "journalctl -xe" for details.
A dependency job for zfs-import-cache.service failed. See 'journalctl -xe' for details.

I now did the install of zfs again so I could take a closer look at the problem but this time the install went flawless.

If I have understood it correctly so will not the GUI work and I will have to use CLI to set up zfs. If so, I1m not sure if I will be able to do that without doing a lot of research before. Do you think it will be a big difference between zfs and the Raid 5 solutions I'm running now?

Do you know if I can add something like this in the Target box on my tgt target setting to get CHAP auth?

incominguser my-user-name and-my-password

Thank you for taking the time to answer my questions.

Quote from chente

The ZFS plugin in OMV5 is fully functional. It would not be the same case in OMV6, it is not fully supported yet.

To configure ZFS you can do it from GUI without any problem. You will be able to configure most of the options. If you are looking for more specific options, you will have to resort to the CLI, but it is not usual.

The difference between ZFS and mdadm is basically the way the data is handled. ZFS is a copy on write system, mdadm is not. ZFS protects against bitrot, mdadm does not. ZFS offers a simple and versatile pool configuration, as opposed to mdadm. ZFS is a more modern system than mdadm and in constant development. mdadm is a fully developed system, albeit an old one.

In terms of access speed, I guess there will be no difference.

Since I at this testing moment have different sizes of my hard drives it will rule out zfs if I got it right. But I did see some performance tests of ZFS compared to raid and it seems like ZFS is faster. Do you know how it works to add more drives to a ZFS pool at a later time after installing a RaidZ? I need the extra security by running at least Raidz1 of course, that will not give me any better write performance to the system.

So for the moment, I will keep on my testing on my Raid5 system and will see how the speed holds up when my 10Gb network equipment arrives (hopefully) next week.
Once again I will have to thank you for the explanations of the ZFS

Quote from chente

This manual, although old, its concepts are maintained, it is very easy to read and very illustrative. If you are going to use ZFS, it is very interesting to read it. https://pthree.org/2012/04/17/…l-zfs-on-debian-gnulinux/

Really interesting readings and I'm now sure I would like to try out ZFS as soon as I can buy a couple of more hard drives and an SDD for the SLOG/SIL.

I have now done some file transfers (23GB video file) across my system. With my 1Gb network cards and 1Gb unmanaged switches I get numbers like this:

Windows to iSCSI server between 60-120 MB/s ((Very unstable speed)
Windows to SMB on the same server 11MB/s
Windows to Windows the same 11MB/s as to the server.

The last peak is my iSCSI transfer and I guess the two small one is my SMB transfer. Is SMB supposed to be this slow?

Quote from chente

If the network is optimal, the speed should be around 100 MB / s. In my case I succeeded when I changed the router. The router provided by my ISP is real rubbish.

You will have to investigate the hardware that makes up your network in addition to the server configuration.

I am no expert on this. A search of the forum will provide you with threads on this topic.

I will do it as soon as my 10Gb system is up running. I will get a managed switch or two and much more control over my network. My network right now is far from optimal.

100MB/s will be 800Mb/s and is a little low for me 120MB/s that is 960Mb/s sounds much better. Why does Microsoft use MB/s for file transfer? Just confusing!

I have now started to copy my photo archive to my iSCSI drive and it looks good so far, almost maxed out on my network speed and that must be great.