# \#zfs **URL:** https://forums.spacerex.co/tag/zfs/52.md [Latest](https://forums.spacerex.co/latest.md) · [Categories](https://forums.spacerex.co/categories.md) · [Tags](https://forums.spacerex.co/tags.md) --- ## [How do I copy data from a ZFS external hard drive to Synology?](https://forums.spacerex.co/t/how-do-i-copy-data-from-a-zfs-external-hard-drive-to-synology/3566)
**Author:** [@Pfilly](https://forums.spacerex.co/u/Pfilly)\ **Replies:** 1\ **Last updated:** [February 5, 2026, 8:07pm UTC](https://forums.spacerex.co/t/how-do-i-copy-data-from-a-zfs-external-hard-drive-to-synology/3566 "2026-02-05T20:07:13Z")
New Synology user here. I came from a trueNAS system that was built from a crumby computer system. The motherboard gave out, and I decided to make the switch to a more user-friendly system. I have backups of my data on … --- ## [My TrueNAS Scale custom configs to maximize ram usage and use more metacaching](https://forums.spacerex.co/t/my-truenas-scale-custom-configs-to-maximize-ram-usage-and-use-more-metacaching/937)
**Author:** [@Will](https://forums.spacerex.co/u/Will)\ **Replies:** 4\ **Last updated:** [August 2, 2025, 10:07am UTC](https://forums.spacerex.co/t/my-truenas-scale-custom-configs-to-maximize-ram-usage-and-use-more-metacaching/937 "2025-08-02T10:07:55Z")
Overview Wanted to add a list here of my custom configs that I use to change how TrueNAS Scale uses RAM. Basically linux ram could be as high as 2x usage then what its expected due to fragmentation, so this commit update… --- ## [L2ARC for SSD pool: gen3 vs gen4 M.2 SSDs](https://forums.spacerex.co/t/l2arc-for-ssd-pool-gen3-vs-gen4-m-2-ssds/988)
**Author:** [@Joss](https://forums.spacerex.co/u/Joss)\ **Replies:** 3\ **Last updated:** [August 11, 2023, 4:24pm UTC](https://forums.spacerex.co/t/l2arc-for-ssd-pool-gen3-vs-gen4-m-2-ssds/988 "2023-08-11T16:24:17Z")
As @Will said in this YouTube video, a Layer 2 ARC might even be detrimental if you already have an SSD pool. So I calculated this, and he’s right. (Just idealized numbers, of course.) Let’s say you have 7 x 4TB SATA SS… --- ## [PCIe M.2 NVMe for storage array](https://forums.spacerex.co/t/pcie-m-2-nvme-for-storage-array/977)
**Author:** [@Joss](https://forums.spacerex.co/u/Joss)\ **Replies:** 0\ **Last updated:** [July 25, 2023, 8:24am UTC](https://forums.spacerex.co/t/pcie-m-2-nvme-for-storage-array/977 "2023-07-25T08:24:05Z")
Ever since the release of the Flashstor and this mini NAS PoC I’ve been thinking about using M.2 (gen3) for my home server, if I build it myself and don’t buy a Synology. Would you think that’s safe for data storage? I … --- ## [One of the best ZFS tunable parameters out there - ZFS.arc\_meta\_min](https://forums.spacerex.co/t/one-of-the-best-zfs-tunable-parameters-out-there-zfs-arc-meta-min/601)
**Author:** [@Will](https://forums.spacerex.co/u/Will)\ **Replies:** 2\ **Last updated:** [June 26, 2023, 2:40pm UTC](https://forums.spacerex.co/t/one-of-the-best-zfs-tunable-parameters-out-there-zfs-arc-meta-min/601 "2023-06-26T14:40:26Z")
So one of the best tunables for ZFS is setting the arc\_meta\_min parameter to something like 10 gigs, if you have more than ~32 gigs of RAM. Metadata is incredibly small on ZFS, so my entire 40 TB system has only about 7 …