My search for a storage system replacement
Background
I currently use a NetApp Storevault S500 in an SMB environment. That NAS has been great for us. It runs a version of NetApp's Data ONTAP. Like all NetApp filers, snapshots are instantaneous. We run nightly backups off a snapshot to get a consistent dataset. We also run hourly snapshots extending back 24 hours, nightly snapshots extending back 2 nights and weekly snapshots extending back 2 weeks. Someone in our office is pulling a file or directory from those snapshots nearly every day. They have been life savers.We run the Storevault in what NetApp calls RAID-DP, which is similar to RAID 6. That allows for 2 drives to fail before we lose data.
We don't use all that much storage compared to most businesses. About 600 GB so our needs are modest. The problem is that the Storevault has been discontinued for years. We have no hardware support so if there is a hardware failure that is all she wrote for the Storevault. We used to have SDLT tape backups in a grandfather - father - son scheme using Arkeia as the software. Arkeia is being discontinued by Western Digital and the SDLT tapes were pretty expensive. Their life span was limited too. Recovery of all that data from tape would have been a long process. So we switched to a round robin of Western Digital My Book external drives with ethernet ports. Plug it in and at midnight a GoodSync job fires up on one of our workstations and updates the My Book from the nightly snapshot on the Storevault. Shut the My Book down the next morning, plug a new one in, and then take last night's drive offsite. The advantage of this setup is if the Storevault ever went down, the My Book could be put online and we were back up and running instantly. Maybe not fast when serving our users but at least we could limp along until a real NAS was put into place.
Given the risk of the Storevault failing, and our storage need slowly growing towards exceeding its capacity, I decided to begin a search for a replacement.
NetApp
Since we love the feature set of the NetApp OS, NetApp was a natural to look at. I got a quote for a FAS2520, 6x2TB SATA drives with 3 years support for $8950. That would give us 4.5 TB of usable storage when configured to run RAID-DP. Not bad. After seeing comments on the web that they would nail us for support for years 4 and 5 I got a re-quote for 5 years of support for $9850. That seemed pretty reasonable for what we wanted. But before pulling the trigger I decided to look around.
Alternatives
Since instant snapshots was a big driver for us I started with that. I quickly came across a file system that came out several years ago called Btrfs. It was being developed for Linux and featured the same pointer based technique NetApp uses for snapshots. Ok sounds interesting but I am not about to roll my own storage solution. Been there many years ago and it was a royal pain. Sucked up a lot of time in maintenance. So what products use this file system? Turns out Netgear rolled out a line of NAS boxes using that file system in its ReadyNAS systems in 2013. Synology was just starting to use it in 2015 in a subset of its NAS line. I decided to look at ReadyNAS since it had been around for a while. The reviews, which were mostly targeted at home users, looked good. But our environment is SMB so I was a little leary. However, the price is attractive. An SMB oriented ReadyNAS 516 6 drive bay system was just under $1200 without disks at Amazon.
ReadyNAS
When you buy a unit from the top tier storage vendors, you have to use their disks. The drives have secret sauce on them and without the sauce a drive does not work in the unit. NetApp gets a huge amount for their drives. I seem to remember $1100 for a 2TB drive, 10x more than a consumer grade drive. On the other hand, Netgear allows you to buy and populate the unit with commercially available drives. If you want support you have to use a drive from their approved list. I have had good success with Western Digital so I found a 3 TB drive in their Red line of drives specifically designed for NAS applications. $106 from Amazon. In total a 516 with 6x3TB drives would run about $1825 including 5 years of hardware support. Adding 5 years of software support brings the total to about $2500. Using Netgear's RAID calculator, 6x3TB disks in a RAID 6 configuration gives us 10.9 TB of usable storage, over 10 times what we need now. The difference between the NetApp quote and a 516 would be $7350. With that savings we could get a second unit and replicate the data to an offsite location and still have money left over.
But would a ReadyNAS do what we needed it to do? In my experience the only way to be sure was to try it. I decided to get an RN204 4 bay unit targeted at home users and try it out. The OS is the same but the performance in an SMB environment would be less than ideal due to the lower end processor and memory in the unit. Populated with 4 WD Red 3TB drives in a RAID 6 configuration would set us back $725. A cheap test. If it did not work out I could ebay it or find another use for it.
ReadyNAS RN204 testing
Setup
Install and setup was easy. I was a little concerned by the fact that configuration of the unit occurs from a web site that Netgear has. I'll have to look into that later since login info was set via the web site. I'm concerned that if the website got hacked, our data would be exposed. The website got a C grade on security here.
There was some monkeying around with setting up the RAID-6 in what Netgear calls a "traditional" configuration. In that configuration you cannot expand the volume. But you can have a hot spare drive which we want. You can't have a hot spare with their X-RAID configuration. I don't recall exactly what the monkeying around entailed. It had to do with the fact that the unit wanted to initialize in RAID 5 and I wanted RAID 6. I found on the web that upgrading from RAID 5 to 6 took someone 2 weeks. I flushed the drives and started from scratch with RAID 6. The initialization of the array took 27 hours. Be patient I guess.
Further posts will deal with specific testing I did.
