Is it possible to use an external usb hub/ethernet adapter in FreeNAS?

[travanx]

yup, even HP MicroServer shipped with ECC, 2GB only though, so much about pinching pennies as what exactly are you going to do with 2GB of RAM these days?

My Lenovo TS140 server came with 4GB of ECC. So what did I do? Added a stick of 8GB. ECC ram isn't exactly expensive compared to a full build out, mainly the cost of hard drives. So why skimp out up front? In a sense the minimum requirements to build a freenas server are relatively cheap to build the whole thing.

 

[babaroga]

Well, if you understood how ZFS actually works, then you wouldn't say that. It is not a question about light use, heavy use, or any other kind of use. ZFS uses the memory in part of its operation, and if the memory is not ECC then you run the risk of corrupting your data and never knowing until it is too late. Other file systems, such as NTFS (Windows) don't do this.

Everything will work fine, until there is an error and then it breaks. Worst part is, that you might actually make backups of corrupted data and never know it until you try to access one of the corrupted files.

I do understand how ZFS works, and hence my point on RAM memory in general. If it is so "prone to errors" as you are implying, then it would be unfit for the purpose of using it all together. Hence is my saying what is being used in big corporations and that a lot of calculation of all data is done on the desktop and not on the server. Error correction would have to be done in "software". And here I am not talking banks, but scientific operations and research facilities. Are you expecting to say that some of those are corrupted because being executed and stored for a long time in non ECC RAM? How about IBM mainframes now. Those have ECC RAM from their inception in 1960s, however, they still have double or triple execution paths for each task and then compare results...now that's what I call redundancy check :)

So, if you are referring to this research http://research.cs.wisc.edu/wind/Publications/zfs-corruption-fast10.pdf fine, but that was "rigged" by assuming that RAM is faulty by default and will have hard error after specific period of time and then ZFS cannot deal with it. My opinion to that is Garbage In, Garbage Out principle, as if information to be saved to disc is corrupted in RAM, it will be corrupted on disc as well, and not only on ZFS level, but OS as well, and it would be task of the OS to detect those and inform users (or shut itself down). Only downside of ZFS is when data is flushed back to disc from ARC, but in that case your memory must be totally screwed...

But, back to the point, as ECC RAM today is priced just 5-10% more, it is worth having it for the peace of your mind...

 

[pschatz100]

I do understand how ZFS works, and hence my point on RAM memory in general. If it is so "prone to errors" as you are implying, then it would be unfit for the purpose of using it all together.

As I said before, it's not about what the computer is doing or what kind of data you work with. It's all about the file system being used. ZFS is a copy-on-write file system. If you know what that means, then you know why ECC Ram is important when using ZFS. If you don't, then you do not understand ZFS.

But, it's your data...

 

[babaroga]

just don't talk to me about COWs, hence battery backups on RAID cards with cache memory, and not to day that UPS is a must as well alongside ECC :)

Forgot one more thing, people should make sure they have backup policy in place for important data and not to rely on ZFS being "omnipotent". Just my 2p (or rappen now) worth