Sudden Transfer Drops

[Nexitus]

Hi,

I have a FreeNAS server setup with 8x 2TB drives in a ZFS RAID, in which my desktop is connected to via iSCSI.

I was doing a 400gb+ transfer to the server one night to backup some files and noticed that during the transfer process (about 20% left), it had stalled. And what I mean by stalled was that, through Task Manager, the Disk Active time of the FreeNAS was 80%+, the Network transfer was Sending 200+ Mbps and Receiving some 30Mbps without actually transferring anything between the two computers.

This caused all internet-related applications on the computer to freeze up and the only recourse was to restart the computer. With that, I tried to transfer the remaining files, but now, everytime I try to transfer any files to the FreeNAS, the files would go through the initial burst and drop off immediately and just stall.

Since there is no software and hardware changes to both computers and all drives are being reported healthy, I am not sure what is happening.

I should add, grabbing any files off of the FreeNAS is fine.

Any help would be much appreciated.

Thanks!

 

[rm-r]

Have you tried via a samba share?

 

[Nexitus]

Unfortunately I don't think I can do that since the whole NAS is partitioned into as an iSCSI extent.

However, I did a little digging into Event Viewer and it seems that I'm getting a lot of IO Operation at Logical Block XXXX has retired.

So I'm now performing a chkdsk and check SMART to see if any drives are failing.

Note: These are WD Green 2TB drives, so it failing wouldn't be totally surprising albeit they're technically "healthy" right now.

 

[cyberjock]

How much RAM do you have on your FreeNAS server? As soon as you start using iSCSI on a FreeNAS server your system requirments skyrocket unless you want the I/O latency errors you are getting. The only solution is to give up on iSCSI or up your system requirements. And before you tell me your system requirements I can already predict you will later say "I don't want to spend that kind of money for iSCSI on ZFS!"

 

[Nexitus]

Ha!

Actually I was planning on upgrading the RAM already. I know by ZFS requirement I'm already 2gb shy of the minimum for ZFS (RAIDZ2). This is a 10TB NAS after all.

But here, its currently a E35M1-Pro (E-350) with 2x4gb (8gb) RAM, and 8x2TB (10TB RAIDZ2).

Im totally willing to spend the money, and was thinking I should go full in on a hardware raid so I dont need to deal with issues like this.

 

[cyberjock]

Yeah, you are probably talking 32GB of RAM minimum for good iscsi performance.

Are you talking hardware RAID and ditching FreeNAS?

And 8x2TB in a RAIDZ2 gives you 12TB of disk space. ;)

 

[Nexitus]

Yea, I'll probably not get to the 32gb with this motherboard, but I think 16gb is not too bad. I'm not looking for stellar performance, but just to fix this issue right now.

I thought FreeNAS supported Hardware RAID (via LSI MegaRAID Controller).

Also, FreeNAS reports just under 10 TiB with the setup :(

 

[cyberjock]

Yeah, you probably because of the TB not being equal to a TB to the hard drive manufacturers, plus some overhead, etc etc.

FreeNAS supports hardware RAID, but you should NOT mix hardware RAID with ZFS. And after 9.2 FreeNAS is getting rid of UFS, so that'll be gone for good. Think about all of that and its not a far jump to then say "FreeNAS doesn't support hardware RAID" because you'd be crazy to use it. ;)

 

[Nexitus]

I didn't know that. Thanks for the info!

I think, I might need to completely relook at my hardware for my NAS a bit and see whats a good next step if I need any.

 

[Nexitus]

One more question, if I forfeit on iSCSI and move onto Samba, would that lighten the load and "improve" or lead to more consistent performance?

 

[Knowltey]

It could. My NAS is accessed via Samba. In it's old configuration it had an issue where when transferring it'd transfer at 60MB/s for like 10 to 15 seconds and then would stop transferring altogether for like 5 seconds before resuming again between 50 and 60MB/s and then lather rinse repeat through the whole transfer. It ended up being resolved when I changed from a single disk configuration to RAID1.