Hello,
even after reading a lot about TrueNAS and ZFS, there are still some points unclear to me. Maybe, someone could help to increase my understanding as a beginner.
Thomas
even after reading a lot about TrueNAS and ZFS, there are still some points unclear to me. Maybe, someone could help to increase my understanding as a beginner.
- Datasets & Data Organization
- How to organize the personal data into datasets and pools? One solution I have seen is, to organize the data regarding its importance into datasets, so that datasets can simply be backed up based on their importance. Do you have examples on how you have organized your datasets?
- There are a lot of discussion in the forum here that on a highly filled Pool/Dataset the performance strongly decreases as well as a 100% filled pool cannot delete files anymore (because of the Copy-on-Write mechanism). Is there a simple mechanism to reserve around 20% of the disk space for the case of emergency? Does it work to simply create an additional dataset with some reserved space that can be reduced to zero in case we run out of space and to be able to delete some files? (sorry for this question, which was discussed a lot here in the forum, but there are so many different answers and I have not really got the point what works and what not)
- VDevs
- I have found that TrueNAS recommends WD drives. However, is it recommended to mix drives of different makes and models in a VDev to avoid data corruption because of bugs in a specific drive model?
- How does TrueNAS and ZFS behave in case different makes of drives are used? For example, if a 8TB drive from WD and Seagate are combined, does TrueNAS automatically use the minimally smaller drive size?
- ZPools
- I have learned that ZFS "fragments" over time and that a defrag is not possible. The only way to "defrag" seems to be to remove the whole pool and recreate it. Would it also be possible to create a new pool, copy over all data to the new pool and simply redirect all "references" from the old pool to the new one?
- Are there any rules on how to arrange Pools over VDevs? For example, if there are three VDevs A, B, C, is it possible to create one Pool spread over VDev A and B, another Pool over VDev A and C, and one pool only located on VDev B?
- Encryption
- Are you recommending to encrypt complete pools or to encrypt on dataset level?
- TrueNAS, SSD & TRIM
- Is it necessary to use TRIM for SSDs?
- Sometime it is recommended to use SSDs supporting RZAT (Deterministic TRIM; Deterministic read ZEROs after TRIM (rzat)), while other sources write "TRIM is not used and not needed due to ZFS's copy on write drive leveling.".
- Does encrypting pools on SSDs make problems (because of possible Write Amplification)?
- Optimizations for SSDs
- Which configuration parameters should be optimized for SSDs?
- Disable atime updates?
- Using compression and deduplication to reduce the writes to the SSD vdevs, prolonging the lifetime.
- Sector Size
- How to configure the logical sectors, block sizes, etc.?
- Which configuration parameters should be optimized for SSDs?
- Config DB
- Do you recommend to place the Config DB on a separate Dataset or Pool? I assume that an own Pool has the advantage that it can simply imported after a new TrueNAS installation to re-import all TrueNAs settings without the need to directly import also all user data pools.
Thomas