[Leica] about NAS devices

[Spencer Cheng]

Very good suggestions, Brian. 

I’ll add a few more. This works for me. YMMV.

1/ Don’t buy cheap hard drives. I’ve had too many Western Digital and Seagate consumer HDDs fail on me. Seagate, in particular, went through a period of very high failure rates a few years ago. I no longer trust them. For NAS type of use, I now by WD Ultrastar HDDs (which use to be Hitachi Ultrastar and before that IBM Fireball) in 14TB or bigger in size when the price ($/TB) is reasonable. 

2/ I no longer use RAID of any sort, not even RAID 1 (1:1 replication) because RAID disk rebuild when one disk is replaced has too high probability of failure for disks bigger than about 750GB. My version of RAID 1 is basically a 14TB Ultrastar HDD in a tiny backup “PC” connected to my NAS which has various HDDs and SSDs in it. Like Brian, important data is replicated to the backup “PC”. 

3/ I use TrueNAS to run my NAS but I am a geek and I like to tinker a bit. I like ZFS rather than whatever file system commercial NAS uses, to achieve better data integrity. One thing TrueNAS/ZFS supports is is both internal and remote replication. I use both. I need to take my backup “PC” to my friend’s place and do all the firewall and remote configuration.

4/ ZFS allows me to encrypt the data on the NAS and the remote “backup” PC and still do remote replication. Not perfect since ZFS needs a bit of metadata at the remote end to enable remote replication but no decryption or encryption keys are stored on the remote backup.

5/ Never *EVER* buy 3.5” hard drives over the net and have it delivered if you care about reliability. This is the one thing I will always buy locally. The drive mechanisms in modern HDDs are delicate things. You don’t know how many times it got chucked around by the courier company(ies). I always go to a local shop and pick up in stock HDDs. Not a guarantee but much more likely they would drop a sled of HDDs delivering it to the store. 

6/ Corollary to #5 is if you receive a HDD by mail from warranty claim, don’t put anything you care on it. Firstly, the warranty drives are typically returned drives which were re-tested and deemed acceptable by the manufacturer. Secondly, it’s shipped by courier to you which means it’s suspect even if it was perfectly fine leaving the manufacturer.

Regards,
Spencer

> On Oct 25, 2022, at 15:46, Brian Reid <reid at mejac.carlsbad.ca.us> wrote:
> 
> The term "NAS" stands for "Network Attached Storage". But NAS boxes are being used in other ways. Here's some background and explanation.
> 
> NAS boxes provide 3 core functions:
> 
> 1. Aggregation. You can have a bunch of drives but talk to them as if they were just one drive. This way you don't have to remember which drive you put something on. A NAS is seen by your computer as just one drive, regardless of how many drives are actually in it.
> 
> 2. Access. This is the "NA" part of NAS, and is why they were invented. If you have a NAS box and it is connected to an ethernet, then more than one computer can access it without you having to move any wires.
> 
> 3. Safety. NAS boxes can (if you want) combine multiple drives in such a way that if one fails, you haven't lost any data, and theoretically you can replace that one failed drive and keep going. Doing this gives you less overall storage (you have to store multiple copies of data in order to make this work) but more reliability.
> 
> There are dozens of other non-core functions that add stress, complexity, and marketing advantage to a NAS box. You don't have to use any of them, but some are awfully convenient.
> 
> If two computers are trying to access the same storage, they need to take special care to make sure they don't trip over each other. If Computer A and Computer B are trying to update the same storage at the same time, it will make a mess. To prevent this from happening, software programmers use a technique called "file locking". Unfortunately, standard file locking techniques don't work with ethernet, so many applications (such as Lightroom) just say "sorry, you can't do that". Lightroom won't let you access a catalog across an ethernet because it doesn't want to be responsible for getting the locking done right.
> 
> If you use a NAS box but access it by a USB cable, then you are not using it via a network and therefore are not subject to network file locking problems. You get functions 1 and 3.
> 
> I use NAS boxes extensively, but I am a sufficiently jaded computer systems person that I will never trust them to do simultaneous shared access because of the inherent complexity of those file locking protocols.
> 
> But this is just me and my family. When I managed the IT department for a big company, I couldn't make "no sharing" rules, so instead I had to make and enforce rules for sharing.  I am long gone from the big companies whose IT departments I managed, but my rules remain pretty much as I wrote them, which is:
> 
> * Never edit on a NAS. Make a local copy and edit that, and put the edited copy back when you are done. Even though a NAS can be used as a virtual drive to edit in place, don't do it.
> 
> * Devise, use, and enforce a system to coordinate your updates with other people. I always use a "check-out/check-in" model. To edit a file, check it out of the library. When you are done editing and have uploaded the revised version, check it back in. The check-out process must prohibit the checking out of a file that someone else has checked out.
> 
> My personal process to manage my files (including photographs) is to keep the master copy of everything on a NAS at my house, to have that NAS automatically copied every night to storage that is not in my house, and to do check-out/check-in of files from the home NAS to my computers. The reason I use check-out/check-in even though it's just me doing it is that I have more than one computer. If I start an edit on my laptop, and then try to edit from my iMac, it will not let me do it.
> 
> Because I am paranoid and suspicious, I actually have 2 NAS devices from different manufacturers at my house, and replicate the master copy to the mirror copy by an automatic means. (Master is ReadyNAS, mirror is TrueNAS).
> 
> I also run Time Machine service on my master NAS device. Time Machine data is part of what is copied every night to offsite storage.
> 
> 
> 
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