January 25, 20251 yr Hi everyone. I'm new to UNRAID and NAS, I'm running UNRAID 7, 1 parity drive, 5 array drives. 26TB Seagate exos On a Terramaster T12 500 pro. I'm using AJA system test to check speeds. I know it's a single drive system, but I"m curious what kind of speeds I should be seeing for sustained data transfer?
January 25, 20251 yr Community Expert Reads should be single disk max sped, writes around 60MB/s with default write, max single disk write speed with turbo write, assuming no controller bottlenecks.
January 25, 20251 yr Author Ok. thanks for the info. Seems like it's the parity drive that's causing a 50% speed hit? (I have about 120tb to transfer, so trying to do that as fast as I can. 😃
January 25, 20251 yr Community Expert Just now, cidion said: Seems like it's the parity drive that's causing a 50% speed hit? (I have about 120tb to transfer, so trying to do that as fast as I can Parity does cause a big performance hit on writes which is one reason we often recommend doing the initial data load without a parity disk assigned. However you may want the parity assigned even from the beginning to guard against disk failure so you have to decide if the trade-off is is worth it. Once you have the initial load done then you can use the Unraid 'cache' facility (using a a pool outside the main array) on shares to avoid seeing this performance hit on writes during normal daily running.
January 25, 20251 yr Author Ohh. that's a good idea. Most of this data is cold storage. Non critical, and I'll have a 2nd copy, so that seems doable. So I'd just stop the array, unassign the drive, turn back on array. Then after the transfer is done reverse that step? For the cache, I have 2 nvme slots on my system. I assume I could put a couple in there and that would help with day to day usage and not use a drive slot?
January 25, 20251 yr Community Expert 20 minutes ago, cidion said: Then after the transfer is done reverse that step Yes. At that point Unraid would rebuild the parity based on the data currently on the drives. 21 minutes ago, cidion said: For the cache, I have 2 nvme slots on my system. I assume I could put a couple in there and that would help with day to day usage and not use a drive slot? Not quite sure what you are asking? All drives count towards the licence. However if you are asking about slots in the main array then they would instead be added as a pool outside the main array. Note that pools are not restricted to acting as a 'cache' for shares that end up on the main array. They are often used as 'application' drives to support docker containers and VMs with maximum performance. Not sure if you want to use either of these on this server?
January 25, 20251 yr Author Ah sorry. I'm still asleep. This is a 12bay enclosure I'm needing to get as much storage out of. So making the NVME drives the cache would let me keep the bays for storage. If I'm understanding right.
January 25, 20251 yr Community Expert 28 minutes ago, cidion said: Ah sorry. I'm still asleep. This is a 12bay enclosure I'm needing to get as much storage out of. So making the NVME drives the cache would let me keep the bays for storage. If I'm understanding right. Yes. It is normally a good idea to only use NVMEs in a pool as that is where they perform best, and in addition array drives cannot be trimmed which might lead to a loss of performance over time
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