#Zfs raid level openzfs how to#

So, you can indeed increase your pool over time by adding VDEVs by a minimum of 2 disks for mirrors (RAID1), 3 disks for RAIDZ (RAID5) or 4 disk for RAIDZ2 (RAID6).The popularity of OpenZFS has spawned a great community of users, sysadmins, architects and developers, contributing a wealth of advice, tips and tricks, and rules of thumb on how to configure ZFS. The moral is, don’t simply look at the total number of parity drives and think “more is better”. The 4x 3-wide Z1 configuration has an even higher failure probability than the mirrors. Our 6x 2-way mirror pool has 6 total parity drives, but it’s far more likely to fail than either the Z3 or Z2 configurations.

For example, a 12-wide Z3 pool with 3 parity drives is statistically less likely to fail than a 2x 6-wide Z2 pool with 4 total parity drives. The question of translating per-vdev fault tolerance into total pool reliability is more complicated than it might initially appear. If that drive goes, your whole pool is gone. Your extremely fault-tolerant Z3 vdev now depends on that single 12th drive to maintain your data. For example, you could configure an 11-wide Z3 vdev and add a single striped vdev as the 12th drive in the pool. Using identical vdevs is strongly recommended, but it is possible to mismatch vdevs in a pool. The configurations we discussed above all use pools made up of identical vdevs. If a single vdev in a pool is lost, your data is lost. I want to make a few quick points on fault tolerance and pool failure probability before we move on. If you look at part 2 of iXsystems blog post above they mention adding VDEVs to a pool and reliability: I would love to take a closer look at FreeNAS or unRaid + ZFS (with 1 or 2 disk redundancy) but I understand you can’t put more disks in a VDEV that already exists, so in order to expand your capacity you always need minimal 3 disks (right?!)… What is the best file system if you want to gradually expand your data 1 or 2 disks at a time, given the fact I can’t afford to buy 24*14TB (2x including backup!) drives at this point. My question let’s say I invest in a 24 bay (like a net app DS4224). more spinning disks / more data / more bandwidth (right?!).Faster network speeds, (I currently have 10gbe, which for now is good).Virtualization / renders system (thinking about Ryzen or even Epic processor + beefy GPU).More power -> CPU and graphics pass tough (that’s why I think unRaid is a good option).But I want to switch to something more powerful like unRaid / FreeNAS for these reasons: The main function of the Synology’s at the moment is file sharing / backups which work completely fine. We currently have roughly about 244TB’s (x2) of video material. I run a small film production studio and currently we’ve been using a couple Synology NAS systems (5, 8 and 12 bay units all running RAID 5 + backups). Hopfully you can advice me on something VDEV related Fault tolerance per vdev is equal to the parity level of that vdev. If you’re using mismatched disk sizes, it’s the size of the smallest disk times the number of data disks. The effective storage space in a RAIDZ vdev is equal to the capacity of a single disk times the number of data disks in the vdev. Here are the basics for calculating RAIDZ performance, the terms parity disks and data disks refer to the parity level (1 for Z1, 2 for Z2, and 3 for Z3 we’ll call the parity level p ) and vdev width (the number of disks in the vdev, which we’ll call N ) minus p. If you have multiple vdevs, the pool data is striped across all the vdevs. Each vdev can combine physical drives in a number of different RAIDZ configurations. In ZFS, drives are logically grouped together into one or more vdevs. Fault tolerance (maximum number of drives that can fail before data loss)ĭo you need more storage? more speed? more fault tolerance? How you lay them out will cause dramatic differences in in these numbers which is why deciding this is the first step in your plan.Storage space efficiency (usable capacity after parity versus total raw capacity).

These are the metrics to consider when deciding how to layout your drives in FreeNAS.

Zfs raid level openzfs