Backup Hardware Suggestions

[PhiloEpisteme]

Hi folks,

I recently completed my first build. I'm running my system on an X11SSM-F board with an i3-7100 cpu, 32GB ram and 2 storage pools with 1 vdev each composed of 6 2TB and 3TB drives each. The former is encrypted whereas the latter is not. My current backup consists of USB external HDD I had lying around. Time for an upgrade.

After reading though the forums and the resources I have gleaned that USB interface drives are a bad idea.

I've also come to understand the community has generally negative attitudes toward SATA port multipliers.

Ideally I'd run a second FreeNAS system, but I think the cost and lack of an off-site location to run it from might be prohibitive.

I therefore am currently considering external SAS enclosures, one for each pool, connected via an LSI 9207-8e card. I'd have disks on-site in the enclosures for regular backups that I swap out every month or so with off-site disks. I'd like to stick with RAID-Z2 on these enclosures so that in the event I lost my main box and on-site backups I have a reliable backup off-site.

I have several questions then.

First, is the above strategy reasonable? I've seen it advocated for in various places throughout the forums. Are there enclosures folks have used for a long time and had good success with? I don't want to buy a poorly made enclosure and have recurring issues with my backups.

Second, the SAS enclosures I've seen have 1 SAS port per 4 drive bays. If I use an 8e card without an expander I'll be able get, at best, 8 bays; 4 drives per pool. Is it totally unreasonable to do RAID-Z2 on a 4disk setup for backups?

If I wanted to buy a 3-port, 12-bay SAS enclosure is there a way to make use of it without either a 16e card or somehow introducing a sas expander to the mix?

I'm also wavering back and forth on what drives to use for my backup. If I go with an enclosure the drives will not be in heavy use and will often sit in storage. I imagine cheaper non-NAS drives will be just fine for this, yes?

If I did choose to go the route of a backup NAS box and place it somewhere off-site is there then any need for an additional on-site backup? This may make a huge difference in terms of price.

Lastly, how low-end can I go with hardware for a backup NAS box? If I could build a second box out of used parts for only a few hundred dollars more than the SAS enclosures I would be willing to put together a second NAS box instead and find some place to run it from. I like this option because it allows me to grow my backup storage more easily if say I found a used 12-bay rack-mount chassis . The trouble is that it by the time I pick a board, cpu, memory, chassis, HBA, cables, etc I am well over the cost of the enclosures. Much of the cost comes from the CPU and memory. Is 8GB of memory enough for a backup box? I know it is the "lower limit" but how bad is performance on 8GB with say 2 pools at 12TB each? How slow of a CPU will a system like this tolerate? I realize that this may be a rather involved question and I might be better off posting specifics to this in Will it FreeNAS?

Anyway, any advice or help would be greatly appreciated. If I missed something in the forums or documentation that will answer my questions kindly point toward them and I'll get to reading.

EDIT: I posted a potential backup FreeNAS build in Will it FreeNas?

 

[Arwen]

One option is to use a single, very large disk for each pool's backup. That's what I do. I have 4 x 4TB in a RAID-Z2, so max is 8TB. I bought an 8TB disk and re-used a 750GB disk, (the 8TB can backup everything, the 750GB all but the media).

Then you can use an external eSATA enclosure, (without port multiplier).

This has the advantage in that you can add as many backup disks to each pool's backup rotation, as you want or can afford. Plus, easy to take the disk(s) off site in a hard shell case, (like Seahorse).

My example backup scheme is here;

http://forums.freenas.org/index.php?resources/how-to-backup-to-local-disks.26/

 

[PhiloEpisteme]

Hi Arwen, thanks for the reply. I'm certainly aware of the option of using a single large drive. I've seen the post you linked, I found it quite helpful. Are you not worried about issues recovering from your backups if you're using single-disks? Is your approach just to use several large disks off-site in the event one fails?

 

[Logikgear]

If you wanted to go with the 9207-8e HBA and a disk shelf you could go with a Dell SC200 it has two SAS expanders in the back but you only need to connect one with a single cable at minimum. There are two for redundancy and two ports each for redundancy on connection. I currently have a second Freenas box in my rack for a local back up with two large 6tb drives in a mirror that takes an rsync from my primary NAS hourly. I plan to do a BackBlaze B2 back up in the cloud (their costs are very reasonable for my use case)

 

[PhiloEpisteme]

Thanks for the advice. I can certainly save some money if I go with 2 mirrored drives rather than RAID-Z2. I am not prepared to buy a chassis like the Dell SC200 new. I've looked around on ebay for used ones but have not found anything I feel confident about; likely that is due to inexperience with the hardware on my part.

I could certainly save some cash by using a SAS enclosure (no expander) similar to the PC Pitstop J0406T. If I go this route I'll have to do some research to pick an enclosure that is reliable and reasonably cheap. I'm not worried about losing the ability to daisy chain the enclosure with another or the limited ports on the 9207. I've still got 1 8x and 1 4x PCIe 3 slots on my board; plenty of room for an dual 10Gbps NIC and an 9305-16e card for use with SAS expanders for more storage when I do make the jump to rackmount chassis. I could move my 9207-8i to a one of the x4 slots to give me two x8 PCIe slots as well instead of 1 8 and 1 4.

 

[Logikgear]

Your welcome. That enclosure and the 8 bay versions look good. Not much to go wrong with them. If you open them up they are just a PSU and a reverse brake out cable. It's the same thing I use for testing HBAs and doing drive burn-in. Like in the picture below. I'm testing a 9207-8e and 4 WD Re drives I picked up used. There isn't really much to go wrong with those disk shelfs if you get one used. The Expanders, PSUs and backplanes are relatively cheap. I plan to pick one up in the next free months.

 

[Arwen]

Hi Arwen, thanks for the reply. I'm certainly aware of the option of using a single large drive. I've seen the post you linked, I found it quite helpful. Are you not worried about issues recovering from your backups if you're using single-disks? Is your approach just to use several large disks off-site in the event one fails?

Since I use my FreeNAS as a storage and backup destination, in theory I would have to loose a source disk, 3 disks in the NAS, AND both backup disks before I would loose data.

My backup disks are all ZFS now, just so I can detect any bad blocks easier. (I have 2 x 320GB for client backups as well. They use ZFS too.)