[My previous message was somewhat garbled when reflected back at me. It looks
better in the archives here:
https://marc.info/?l=openbsd-misc&m=161902769301731&w=2. I’m resending as
plain-text to see if the problem is on my end.]
I’m running OpenBSD on top of bHyve using virtual disks allocated out of ZFS
pools. While not the same setup, some concepts carry over...
I have two types of pools:
1) an “expensive" pool for fast random IO:
- this pool is made up stripes of SSD-based vdevs.
- ZFS is configured to use a 16K recordsize for this pool.
- good for small files (guest OS, DBs, web/mail/dns files, etc.)
- When ZFS is told to use the SSD, it starts the partition
on sector 256 (not the default sector 34) to ensure good
SSD NAND alignment.
2) a less-expensive pool for large sequential IO:
- this pool is a single RAIDZ2-based vdev using spinning rust.
- ZFS is configured to use a 1M recordsize for this pool.
- good for large files (movies, high-res images, backups, etc.)
Virtual disks are exposed to the OpenBSD guests from both pools. The guest’s
root-disk is always allocated from pool #1. Typically, a second
application-specific disk is also allocated from pool #1 (e.g., /var/www/sites
on a web server, /home on a mail server, etc.). Only in special circumstances
(e.g., a media server) is a disk allocated from pool #2.
This arrangement steps around needing to read/write 1M blocks for each small
file access, and also the possibility that a guest accessing a given block will
span more than a single physical block.
Can VMWare virtual disks be configured similarly?
K.
