A friendly, hands-on look at whether to split ZFS log and cache in your Proxmox setup

As of October 14, 2025, I’ve been tinkering with a Proxmox ZFS setup on my home server, and I want to share what I’ve learned about using separate partitions for ZFS log and cache. The goal isn’t to chase the latest trick, but to build something reliable that doesn’t wear out SSDs faster than it should. If you’re playing with Proxmox at home and want a sensible starting point, this bite-sized, friend-to-friend guide might help you think through your own setup.

What I learned from my Proxmox journey

My home server runs on an i5-3570K with 32 GB of RAM and a RAID 10 array across six drives (four 1 TB and two 6 TB). I’ve run several LXC containers for Samba, Jellyfin, and a few other services. Early on, I read about keeping ZFS log (SLOG) and ZFS cache (L2ARC) on separate, fast storage to speed up IO. So I gave my Proxmox ZFS setup a dedicated SSD for SLOG and another for L2ARC. Over years of use, that extra wear on the SSDs added up, and I began to wonder if it was worth it in the long run when the default path could be just as solid.

This isn’t a cautionary tale against ZFS, but a reminder that every extra partition or device adds a wear path and management overhead. If you’re curious about the mechanics, ZFS uses the SLOG (ZIL) to accelerate synchronous writes, while L2ARC can help read-heavy workloads by caching frequently accessed data. Details on how ZFS caching and logging work can be found in more depth at Proxmox’s docs and OpenZFS resources. See: ZFS on Proxmox VE and OpenZFS Main Page.

The case for separate ZFS log and cache

Why would you consider moving ZFS log and cache off the main pool? In theory, a fast NVMe SSD for SLOG can reduce write latency for synchronous operations, and a robust L2ARC can speed up reads that repeat frequently. In practice, the benefits show up under specific workloads—like a busy Plex/Jellyfin library with many concurrent clients or heavy Samba shares. For a small home lab that’s mostly idle most of the time, the gains can be modest, and the wear on extra SSDs may not be worth it.

If you want a deeper dive into ZFS caching and logging concepts, check these sources for background: OpenZFS Main Page and Oracle ZFS Intro.

When a default Proxmox setup makes sense

Starting with Proxmox’s default storage layout is perfectly fine for many homes. If your workload is light to moderate, and you don’t want to juggle extra partitions, stick with a straightforward ZFS pool and the OS install on a solid SSD. The main idea behind Proxmox ZFS setup is to give you a solid, stable foundation; you can always adjust later if you notice IO bottlenecks or write-heavy patterns.

For most users, the default approach provides predictable performance with less maintenance. And modern NVMe drives are fast enough that, unless you’re pushing heavy traffic, the marginal gains from extra ZFS partitions can be small.

How to decide for your own Proxmox ZFS setup

Here’s a practical framework to decide whether to split ZFS log and cache in your setup:
– Analyze workload: Are you running many VMs or containers with heavy synchronous writes? Do you have many concurrent read requests? If yes, SLOG/L2ARC could help.
– Assess wear and tear: Do your SSDs show signs of wear or age? If you’re close to the wear limits, extra partitions may not be worth the extra writes.
– Experiment and measure: Try a baseline Proxmox ZFS setup and monitor with iostat, zpool iostat, and SMART data. If you don’t see real benefits, it’s okay to revert.
– Plan for future growth: A server you use for years benefits from being simpler to maintain. If you rarely touch the logs or the cache, keeping it simple reduces risk.

If you want to read more about ZFS structure and caching, these external resources are helpful: OpenZFS Main Page and Oracle ZFS Intro.

Practical tips for a home server

• Start simple: If you’re new to Proxmox and ZFS, begin with a clean pool using default configurations and a single fast SSD. You can always add SLOG/L2ARC later if you notice IO bottlenecks.
• Use dedicated devices with care: If you do add SLOG, prefer a fast, durable SSD and ensure you have spare wear for maintenance.
• Monitor health: Regularly check SMART attributes, pool status, and IO latency. A sudden drop in performance is a signal to re-evaluate.
• Backup, always: ZFS is robust, but you should still have backups. Consider snapshots for VMs and LXC containers, plus off-site backups for critical data.
• Document changes: It’s easy to forget why you did something months later. Keep a quick note of what you changed and why so you can revert if needed.

Takeaways

• Proxmox ZFS setup can be as simple or as involved as your workload demands. Start with the default, observe your traffic, and only split ZFS log and cache if the numbers justify it.
• Wear on SSDs matters. If you can’t tolerate more writes, or you don’t see a meaningful benefit, it’s perfectly reasonable to keep things straightforward.
• The best setup is the one you understand and maintain. A well-documented, stable Proxmox ZFS setup will serve you better than a labor-intensive configuration that’s hard to manage.

External references that helped shape my thinking: Proxmox ZFS on Proxmox VE, OpenZFS Main Page, and Oracle ZFS Intro.

If you’re curious about the practical implications, give it a try on a weekend. You might end up with a setup that’s clean, fast, and easy to maintain, exactly what a home server should feel like.