Ask HN: ZFS for databases (Postgres) - FreeBSD or *Solaris ? | Hacker News Reader

Ask HN: ZFS for databases (Postgres) - FreeBSD or *Solaris ?

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I am finding measurable IO performance improvements in using ZFS compression on Linux for OLAP workloads. Given that the ZFS on Linux project is still moving to a feature complete release, I am considering an OS with a native ZFS implementation.

Although I am not too familiar with BSD or Solaris, I am considering putting the time into learning some admin skills on FreeBSD, or an OpenSolaris descendant like OpenIndiana, SmartOS, or OmniOS.

For systems where application compatibility is not a concern (a box only running the DB engine), does the HN community have any relevant details to share as to which OS's have advantages in this use case?

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I've used ZFS with mysql on both FreeBSD and Solaris (OpenIndiana specifically). The main problems I found with FreeBSD were not the ZFS implementation, but OOM (out of memory) errors killing off processes (like sshd). Solaris, though extremely annoying to use, offered up a 2-5x performance increase over the same hardware running FreeBSD.

> Solaris, though extremely annoying to use

You can't drop a comment like that without details!

Annoying things I found while implementing solaris (open indiana). All my opinion and may not reflect other peoples experiences.

1. Init > SMF - XML manifests instead of text configs? Very unnecessary. svcadmin took some getting used to, consulted the documentation frequently.

2. Packages - Many packages are available, however we ended up compiling most of our software. That inconvenience was one of the main reasons we left FreeBSD.

3. Chef - At the time there was very little we could do to automate these boxes in our infrastructure.

4. SSH keys in LDAP - I don't recall if we ever got this working. (LDAP tree in Zimbra)

5. ZFS Root - Required us to manually install the OS rather than having it provisioned

6. Learning curve - Though not a strong point if you're dropping a new OS you don't know that well in to a production environment things are bound to break.

Those are the ones I can think of off the top of my head. But like I said earlier the performance increase was quite noticeable and worth it to the business.

Don't do *Solaris, go with FreeBSD if you really don't trust Linux ZFS.

I used to administrate a Solaris box using ZFS. I'm still missing organs from those days (required for sacrifices to tentacled horrors).

Also I was initially confused by your desire to use ZFS with a database until I saw the "OLAP".

Godspeed.

So far I find ZFS "sensible", considering I am no LVM expert.

So far volume creation and snapshots seem straightforward, and it only took a bit of research to find the page size and ARC limits that so far are giving me better than XFS on CentOS.

What future pitfalls am I looking forward to?

I run FreeBSD and Postgres on ZFS. It's been an entirely painless experience. No pitfalls to look out for from where I sit. Your use-case and results may differ.

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