Looking for Hardware RAID Controller Recommendations

[ElliottRT]

I am trying to determine what the best hardware RAID controller would be for a BDR Solution I am building for our clients. Originally, we were using Dell Precisions due to the availability of iDRAC enterprise but are currently evaluating building our own BDR Servers for Failover - Ideally the controller supports RAID 1 and RAID 5 at least, preferably RAID 5 with a hot spare. Does anyone have any suggestions? I am having a hard time getting reliable information from our vendors, and I have no experience with building NAS/BDR servers like this. Software RAID is an option, but I would prefer hardware if possible.

[da na]

The LSI MegaRAID SAS 9271-8i is a solid controller, you can get them for $20-30 on eBay in the US, at least. I have personal experience with the MegaRAID controllers and they're quite good.

[Jarsky]

Dells used to use their Dell H700 which is essentially a rebranded LSI 9271-8i in a different form factor with socketed RAM instead of integrated. 

I still use the 9271-8i's theyre solid and reliable. You just want to make sure you get a BBU (battery backup unit). They support RAID0/1/5/6/10/JBOD out the box, and with an advanced software license you can unlock higher levels of RAID and additional features.

 

The 9261-8i is cheaper for additional features like the CacheCade key if you want to add SSD caching to it but it is only a PCIe 2.0 card vs the 9271's PCIe 3.0 interface. 

 

If you need higher performance such as multiple SSD's then the 9361-8i which has more cache, 12GBps SAS/SATA and uses their newer cachevault power module (capacitors instead of LiON battery)

 

 

[wseaton]

The 700 and LSI models above have also given me good experience, especially when combined with spinning drives.  Orders of magnitude better controllers than lower order controllers like perc 300s, bl 240s, etc which are glorified RST on a board. The later controllers are sone of the worst hardware ever to pollute the server market.

 

If you are running SSD I can't stress enough to get the latest and most capable card. For BDR I'm not even sure if I would enable write cache given its not a particular iOPs pattern that takes advantage of it. Spinning drives however.  always benefit from write cache due to mechanical latency. 

 

 

[bloodthirster]

Why hardware RAID?

 

You have to make sure the RAID HW card is going to be around when the card breaks or just buy a spare.  If you can't, all that data probably can't be accessed since you generally need the same HW RAID card to access the data on the storage drives.  Unless there's a really good reason to get a HW RAID card, it's another point of failure that can potentially leave you without access to the data on the drives.   HW RAID can be good, but especially for one off type of projects, they can do more harm than good.   I'd seriously ask the question if adding another point of failure (which can leave you unable to access your data) is worth the benefit you get from it.

[wseaton]

I'll take a crack at this because bloodthirster has a point.

 

Hardware RAID controllers have caused more enterprise downtime and lost data in my career than any other factor. This includes Ransomware. Also, this isn't focused on just standalone servers running local storage. RAID controllers in enterprise class SAN and NAS units are also on my sh_t list. EMC being by far the biggest offender. I can tell story after story of EMC controller meltdowns wiping out massive chunks of data, wiping out months of E-mails on Exchange servers, ets. Yes, hardware RAID controllers are a statistical point of failure.

 

However, so is software RAID. Just look at the adventure Linus had with his own NAS. Uh, PEBKAC. Still, a state of the art motherboard doing I/O processing with Intel or AMD doing the work vs a hardware RAID controller is a no brainer in my book. So, SO many more layers of fault tolerance and error correct let alone thermal tolerance with the software RAID solution using a conventional motherboard.

 

The biggest issue with software RAID I have is solutions for it, unless you are at an enterprise scale, tend to be rather ad-hoc and barely more than DIY. Downloading a LInux distro and throwing it on  'server' doesn't meet the muster when it comes to a lot of IT Director's under scrutiny for security and auditing. Somebody has to mange it, and hardware RAID puts it under a single pane of glass. The better RAID controllers work with iDRAC, iLO, most SNMP monitoring packages, handle hot swapping ,etc. Software RAID solutions tend to be a mixed bag with these functions. Obviously workable, but often not out of the box. Again, not everybody wants to support a Linux server as a NAS, or has the time, or wants to crawl inside a server attaching drives.

 

Software RAID also has performance issues when it comes to spinners and latency. DRAM cache on hardware RAID controllers is mandatory with heavy virtualization loads when using spinners. Boy I can tell stories. However, this goes away with SSD...for the most part.

 

My favorite solution is to run the NAS OS off a small but reliable SSD (Intel Data center grade), and then run the data stores off a separate logical and physical array entirely. Backup the OS to something else, nd there is no point of failure.

 

Ultimately hardware RAID is going away as addressable direct storage takes over. Still, the RAID controllers we suggested above are robust and reliable solutions.