local vs iscsi

[Zedicus]

so i have a NAS that has lots of space for user files and stuff already. my VM host server has some hardware that is slowly failing. i am going to be picking up an Epyc 1u system and i am trying to decide rather i want to just save the hassle and add some local disk to it for the VMs OSs, or actually add the disks to the NAS and connect them via ISCSI. honestly the VMs will be connected to the shared disk over network anyway. adding ISCSI fo an OS LUN just seems like extra work.

am i missing some benefit? ( i run ISCSI at work across a cluster and we have all data flowing through the virtual servers and out, my home setup is more NAS with capability of doing ISCSI if i set it up) backup might be a pro, but i can do backups through the VM host OS too soooo....

i have enough hardware and i could do a 10gb direct connect for the ISCSI so cost is a wash.

thoughts? PROs and CONs?

 

[Biznatch]

If you have 10g and a good array to back it up, do it for fun/experience. I'm running a hyperV cluster with 1u dual core e5 Supermicro servers that use ISCSI on my zfs cluster. Raid 10 s3700 intels for VM storage, and Raidz2 on 4tb for mass/media storage. The raid10 array can easily saturate 10g lan, so I have each 1u server directly connected to the zfs server.

 

[Schmeisser]

I have a Hyper-V cluster in my lab. For a shared storage I am utilizing StarWind VSAN over iSCSI. Local storage is RAID10 HDDs. Each server has dual port 10GbE card for cluster and iSCSI traffic great performing and stable setup.
Depending on your NAS (and its iSCSI stack) you can play with it. However, in my opinion, NAS should be used for storing backups. Run VMs of a local storage to get minimum latency.

 

[_Gea]

It depends

A NAS with FC/iSCSI, NFS and SMB especially from the ZFS area can give some advantages over local VM storage like
- superiour rambased read/write caching. Such a system can deliver > 80% of all reads
from RAM and can transform many small slow random writes to a single large sequential write
- crash redundancy (no write hole problem, to damaged raid or filesystems on a crash during write)
- superiour sync write behaviour compared to a hardware raid with BBU/Flash protection
- Ransomware save data versioning/snaps
- easy backup or replication even with open files, rollback, restore from snap, clone
- virtualisation and movability of storage (no fixed partitions, quotas, reservations)

to name a few