Error Correction Code (ECC) RAM is a special type of system memory. Unlike traditional RAM modules inside your desktop or laptop PC, ECC RAM has an additional chip to store data. This memory chip allows ECC RAM to store ten bits of data per eight bits used by the system, effectively increasing data redundancy and making it possible to detect up to two bits of corrupted data and rectify single-bit errors. Network-attached storage (NAS) servers handle lots of data so ECC RAM may make sense, but not everyone needs it.

What is ECC memory?

ECC memory essentially safeguards your system against data corruption. These errors aren't common at all and you likely won't notice encountering one, but should you be running a server or NAS and are met by flipped bits over time, you may start to see some issues with stored files. Corrupted data may get overwritten instead of correct data inside snapshots, which isn't great for anyone. Should your filesystem run a checksum test or two and encounter a data mismatch, good data could be replaced with corrupted blocks.

This is when problems with data integrity can lead to data loss. ECC RAM will help avoid this by storing more data than required to increase redundancy. A redundant array of inexpensive disks (RAID) is fantastic for protecting your NAS against data loss due to drive failures, but ECC RAM can offer some protection against corruption. ECC RAM is great but so are backups, especially if you follow the 3-2-1 backup rule.

Should you always use ECC RAM inside a NAS?

I've sold you on using ECC RAM to safeguard your data against corruption but now I'll explain why you probably shouldn't buy ECC RAM. The more affordable NAS enclosures likely don't have ECC RAM. The easiest way to check is to log into your NAS and see the hardware report or look up your model number on the manufacturer's website. The Synology DiskStation DS924+ has ECC support but the cheaper DiskStation DS224+ only supports non-ECC RAM. Non-ECC memory is cheaper and usually faster whereas ECC can set you back a small fortune.

Your NAS should always be backed up with a RAID configured for maximum data redundancy. ECC RAM would provide another level of protection against data loss or corruption. It's not required but can prove useful if you're working with data frequently updated on the NAS. Enthusiasts, power users, and server administrators will likely favor ECC memory, but the average home NAS owner can make do with "normal" RAM. Remember to double-check what your NAS supports before buying RAM modules!