8 replies to this topic

[RossCumming]

After quite some time deliberating the pros and cons of different backup mechanisms, I finally chose to go with a NAS drive. The main reasons for this were so that both my iMAC and MacBook can access it via Wi-Fi.

 

So yesterday I finally found time to open the box and set it up.

 

However, it is taking a painfully long time to do the first backup, which I know is "normal" but I just didn't expect the first backup to run into days. I expected it to be a number of hours, but so far 24 hours in and it is about 20% complete!

 

I am backing up around 1Tb of image files and after initial testing of the NAS drive using Wi-Fi, I changed to using it hard-wired into the router because it seemed too slow via Wi-Fi. I have my iMAC connected via the Gigabit ethernet socket to the Gigabit ethernet connection on the router using a CAT6 cable and the NAS drive is connected to the router via normal ethernet connection.

 

Is it normal for it to take this long? I was expecting (hoping) that it would be quicker than this and I am now concerned that if has taken 24 hours to back up around 200Gb of data then if I shoot just one 32Gb card of data and run another back up, it will hours to do this just to do the incremental backup.

 

Anyone have any experience of setting up NAS drives and can give any pointers?

 

Equipment being used is iMAC (with Gigabit ethernet), Western Digital EX4100 (with x2 4Tb Red drives fitted in RAID1 configuration) and BT Homehub 4 router (in the United Kingdom) which does have a Gigabit connection. Cat6 ethernet cable connecting the iMAC to the Router.

 

Thanks,

Ross

[Malice]

The bottle neck is probably the write speed of the NAS.

 

I'm really no expert on this, so please take the following not as solid fact, but rather as ideas floating around my head.

 

From what I've read on other forums, the WD NAS systems don't play to nicely in Mac networks to begin with (I often read about Sinology being recommended). And if I'm not mistaken, writing to a RAID1 setup is even slower than writing to just one of the disks. What I do know is that my (outdated) WD MyBook World Ed. II is awfully slow. Both in reading and writing, even from individual disks.

 

Which protocol are you using? AFP or SMB? Are you running a Time Machine backup or is this a straight copy to disk operation?

 

The first Time Machine Backups always take awfully long. It's not only the total amount of data being pushed to the drive but also the number of files. A bunch of small files will take longer than a single file of the same total size.

 

And another thing: please consider that RAID1 in and of itself is *not* a backup of your data. If you keep the originals on your iMac, it's okay. But please don't rely on the RAID to work as a backup. The redundancy of the RAID is supposed to increase availability/accessibility of the data (as in: you can keep on working, even if one disk dies), but not the safety of your data (one mistake e.g. in the RAID controller and everything's fried, as the second disks is a twin of the first, including the errors; especially with complex constructs like Time Machine backups).

 

To sum up: if you don't need the increase in availability/accessibility, I'd rather run the NAS in JBOD configuration. You have double the space and probably faster write speeds. As for the Time Machine backup itself: nothing really helps. You just have to wait for the first one to finish. The follow ups will be much quicker.

[Jerry_]

Hi Ross,

When you mention "backup" do I read it as "copy", or is there any third party software involved in this process?

If not, the first point to pay attention to is the fact that on an end-to-end communication, the slowest connection defines the overall speed.

In your scenario you have one connection that is on a Gigabit ethernet (1000Mb/s) and the second section on a fast ethernet (100Mb/s) - thus your current end-to-end speed can not be higher than 100Mb/s.

However, taking the 200GB/24 hours, your "observed" speed in bits per second is
200*8*1024*1024*1024 / 24*60*60
= 1,72*10^12 / 86400 = 19,88Mb/s

This raises some questions, as it is 5 times slower then it could be for fast ethernet (the 100Mb/s is an ideal value) - not to mention gigabit ethernet. Could it be that it still communicates over wifi (which would then be then slowest connection in this end-to-end communication)

Also, when you look to the specifications of your NAS it tells that it can reach ideally a READ speed of 113MB/s (big B for Bytes, small b for bits), but I couldn't find the WRITE speed in RAID1. Could you check the manual for this?

Anyway, in order to improve the end-to-end communication, what I recommend to do, is to
- buy a Gigabit switch, which will connect all three devices (router/iMac/NAS) allowing an end-to-end communication at the maximum speed. Those switches are quite inexpensive but will add a lot in the transmission speed.
- deactivate the Wifi on the iMac, if there are doubts that it is used for the transmission
- next, reboot all devices to make sure the good route for the information is used
- preferably use shielded cables, rather than unshielded ones. And eventually move up to Cat6A.

HTH

[Merco_61]

One factor to remember with RAID1 is that statistically, the MTBF is in the region of 80% of a single drive as the risk of either drive falling in the short lifespan range is so much larger. Another thing is that like Malice said, there is, despite the name, no redundancy in the lowest two levels of RAID. A write error on one disk is simply replicated on the other. I agree about JBOD being a better solution as well.

[TBonz]

I agree with all of the above thoughts, but one thing not mentioned is that the backup is likely not the only traffic on the network, so your speed may be slower than the rated speed of the connection...

[RossCumming]

Thank-you very much for all the comments. The backup completed Thursday afternoon so from Monday afternoon until Thursday afternoon!

 

I originally started to use Apple Time Machine via Wi-Fi and then cable but changed to WD's own sync utility ("WD Sync") and left it at that. It looks like it is a copy of the hard-drive and the files are accessible as if they are on the hard-drive.

 

When I changed to cable, I disabled Wi-Fi on the iMAC so I know it was connected via cable only. I think I may purchase a Gigabit switch in the future (Netgear have one that is quite affordable).

 

Now the first sync has been completed, it will be interesting to see how the next one goes........

 

I am hoping it will be quicker and will be an incremental sync with only additions / deletions performed. Not sure when I will try this but it should be relatively soon. The end result is the data is now backed up so I am a lot more relaxed now :-)

 

Again, thanks for all the comments, pointers and suggestions; it is very helpful. Once I have it sorted such that I can access it remotely from my laptop I will probably get some of the IT boffins I work with to have a look it from my laptop and advise.

 

Ross

[Jerry_]

I don't know the exact details of "WD Sync", but as a sync tool its purpose will be to keep a "mirror" of what is on your source drive to the WD NAS.

Therefore the next syncing should just take account of changes in your source drive and thus be relatively fast. (Nevertheless a fast end-to-end connection will help)

Just pay attention to the fact that a sync tool does not keep a history of fileversions (opposite to f.i. a Timemachine backup); i.e. when a file is deleted on the source it will also be deleted on the NAS (during the sync process); the same goes for copying corrupted files - but reading your post, you are aware of this

[Malice]

Talking about simple and easy to use backups, I have to say, I'm really a fan of Time Machine. It's very clever working with all those links to have different points in time to jump back to, without occupying disk space with exact copies of the same file.

 

Needless to say, my primary backup solution is TM (on a locally connected 2 TB USB drive).

 

My secondary backups, I also handle with a sync tool. Now, I don't know WD Sync, but from my experience with the My Book World Ed. II, I don't have much faith in their software products.

 

I'm working with two applications to handle file synchronization. The first (and mostly used one) is called "SyncTwoFolders" it is available for free ("donation-ware"). This one has the option to also add files on the destination disk. I.e. all the files, which are outdated on the destination are updated with their newer versions, but files that have been deleted on the source will not be deleted on the destination.

 

The tool is a bit slow, not too easy on the resources and not very nice to look at, but it works.

 

I've started testing ForkLift as an alternative, but up to now, I haven't come across any real advantages over SyncTwoFolders for these kinds of tasks.

 

 

 

Edit: Typos

Edited by Malice, 04 November 2016 - 01:31 PM.

[M.Beier]

I have 2 NAS at home...

One very fast, one regular..

 

Your speeds are off...

- Sorry about suggestions below, they are if more users are reading in case of considering alike option.

But first of all, when doing photos and storing them, do yourself a favor and get a box with 4 bays... 4 Drives, lets say 8TB each, configurated in RAID5, gives you ~24TB (8TB for failover), or more accurately 21.8TB

 

My speeds at home are

NAS-Powerful (i3-3225K, Dell Perc H710P, 4x F4EG 2TB, 4x4GB ram)

114.35/116.55MB/s

 

NAS-Box (Zyxel NAS, 4x Toshiba 6TB X300)

92.67/53.66MB/s

 

The NAS-Box is maxing out within the 1GB/s limit, and is quite ok for storage, however, if it is files that I need to bring to the PC, I will use the more powerful solution, as smaller files still transfer snappy..

The drives themself are much newer and faster in the NAS Box.