Does ZFS really need ECC RAM?
Conceptually, ZFS does not require ECC memory any more as any other file system. There’s nothing special about ZFS that requires/encourages the use of ECC RAM more so than any other filesystem. If you use UFS, EXT, NTFS, btrfs, etc without ECC RAM, you are just as much at risk as if you used ZFS without ECC RAM.
What does non-ECC memory only mean?
Non-ECC (also called non-parity) modules do not have this error-detecting feature. Using ECC decreases your computer’s performance by about 2 percent. Current technology DRAM is very stable, and memory errors are rare, so unless you have a need for ECC, you are better served with non-parity (non-ECC) memory.
What is non-ECC memory only unbuffered?
Un-Buffered – RAM which doesn’t have buffering circuitry. Servers are the only ones which need this as they have a large number of chips on the board. Non-ECC – RAM which doesn’t have error correction capabilities. Only necessary in servers, data centers, and other such applications, not for home users.
Is ECC memory necessary for FreeNAS?
If your system supports it and your budget allows for it, install ECC RAM. There’s a greater-than-zero chance that corruption could happen to your ZFS filesystem when using Non-ECC RAM. FreeNAS encourages you to use ECC in their hardware recommendations.
Is ZFS better than RAID?
ZFS is an awesome file system that offers you way better data integrity protection than other file system + RAID solution combination.
Do I really need ECC memory?
You need high-end, battery-backed fully hardware RAID with onboard RAM to ensure that you don’t lose data due to a power outage, disk failure, or whatever. So no, you don’t really need ECC RAM in your workstation. The benefit simply will not justify the price.
What is non EEC?
Non-ECC (also called non-parity) modules do not have this error-detecting feature. Any chip count not divisible by three or five indicates a non-parity memory module. Using ECC decreases your computer’s performance by about 2 percent.
What is the difference between ECC and non-ECC RAM?
If you are unsure whether you have ECC or non-parity, count the number of small, black, IC chips mounted on one of your existing sticks of memory. If the number of chips on one side is even, as in 4 or 8, you have non-ECC. If the number of chips on one side is NOT even, as in 9, you have ECC.
How do I know if my RAM is ECC or Non-ECC?
For SDRAM or DDR memory, just count the number of small black chips on one side of your existing memory modules. If the number of chips is even then you have non-ECC. If the number of chips is odd then you have ECC.
What is unbuffered ECC memory?
Unbuffered ECC versus Registered ECC Memory The basic difference is that memory commands in unbuffered memory configurations go directly from the controller to the memory module, while in registered memory configurations the commands are sent first to the memory banks’ registers prior to being sent to the modules.
Is UnRAID better than FreeNAS?
Our take is that FreeNAS is the better solution for those seeking traditional RAID with a tried and true volume manager/file system, while UnRAID is better if you’re seeking maximum capacity for non-critical data sets.
What happens if ZFS is on non ECC RAM?
The scenario usually thrown out is the the much-dreaded Scrub Of Death. TL;DR version of the scenario: ZFS is on a system with non-ECC RAM that has a stuck bit, its user initiates a scrub, and as a result of in-memory corruption good blocks fail checksum tests and are overwritten with corrupt data, thus instantly murdering an entire pool.
How does ZFS save data to the disk?
ZFS gets 0 1 110011 and is told to safely store that in the pool. So it calculates parity data and checksums for the corrupted data. Then, this data is saved to the disk. Ok, not much worse than above since the file is trashed. But your parity and checksum isn’t going to help you since those were made after the data was corrupted.
What happens if the file is corrupted in ZFS?
The file is corrupted now thanks to your bad RAM location. ZFS gets 0 1 110011 and is told to safely store that in the pool. So it calculates parity data and checksums for the corrupted data. Then, this data is saved to the disk. Ok, not much worse than above since the file is trashed.
What happens if ZFS doesn’t match checksum?
Since it doesn’t match the checksum either, ZFS doesn’t overwrite anything. It logs an unrecoverable data error for that block, and leaves both copies untouched on disk. No data has been corrupted.