Search results for query: raidz padding

Thank you i reworked my system for a raidz and not a raidz2 ZFS pool. Final two questions. When giving a virtual machine a drive of lets say 750GB, the summary page says I have a total of 1,2 TB used even though the only storage being used is that 750GB drive. Last question. Can I resize the...

No, you read the table wrong. Rows are volblocksize in sectors. If you got a disk with 512B LBA and have chosen ashift=9 for the pool the 8K volblocksize is the row with "16" (8K volblocksize / 512B sectorsize = 16 sectors). But your pool was probably created with a ashift=12 so your sectors are...

You need to increase the volblocksize if using raidz or you will waste alot of space due to bad padding. A 8x disk raidz2 with the default volblocksize of 8k would loose 2/3 of the raw capacity to parity+padding. If you increase the volblocksize to 16k you should only loose 1/3 of the raw...

several things here. #1 raidz-1 isnt optimal at all. its like a raid5 and with such big disks not that fault tollerant as you might think. theres a chance loosing a junk. also 4disks are suboptimal for either. problem is not total capacity but high capacity over 1.5tb a drive. in any case you...

Ok, but same problem. All raidz arent great as VM storage. And with 6 drives and raidz1 you are still loosing 3 and not 1 drive in capacity because of bad padding if you use 8k vollbocksize, because everything stored will be 66% bigger. Look here. So for example 32K would be a better...

First you are using consumer SSDs. To quote the staffs ZFS NVMe benchmark paper: Consumer SSDs are mostly really crappy at sync or continous random 4K writes. The second point is that you use raidz2. Raidz got alot of overhead because of all the additional parity calculations and write speed...

Since you seem to have a way better understanding on that subject and me getting lost trying to figure it out by myself reading random posts here and there which in most cases makes things worst, in case you could help here is my case The Server will have 4 (6gps sas 10K rpm) 1.2Tb disks in zfs...

It is normal that ZFS will write alot to SSDs. Thats why you should always buy enterprise grade SSDs that can handle some petabytes of writes. Some things that willl cause write amplification: - sync writes (especially if you SSDs don't got powerloss protection and therefore can't use the...

CPU Kerne kannst du gerne Überprovisionieren. Also wenn du nur 2 physische Kerne hast, dann kannst du auch 4 VMs je 1 Kern geben. Das ist relativ unproblematisch, solange die VMs/LXCs die Kerne nur selten auslasten. Eigentlich sollte man aber immer einen Kern frei lassen für proxmox selbst, da...

@guletz Can you tell why you think the blocksize is divided by number of data disk? Because data does not have to be spread into every disk in vdev? The only requirement is that the write size should be multiple of (number of parity + 1)...

Raidz1 ist echt nicht ideal wenn du darauf VMs laufen lassen willst. Gerade wenn du HDDs und keine SSDs nutzt, wo dann ja die IOPs schnell an die Grenzen kommen. Raidz1 liefert dir keine sonderlich erhöhte Schreibleistung oder IOPS. Mit einem Stripped Mirror (ala Raid10) hättest du da die...

Wenn du raidz1 benutzt, dann werden im Idealfall nur 25% der Kapazität für Parität draufgehen. Hast du 4x 2,73TiB wäre also theoretisch 8,19TB von 10.92TB nutzbar. Wenn deine HDDs nun aber 4K logische Blockgröße nutzen (Pool mit ashift=12 erstellt) und du die Volblocksize nicht selbst angehoben...

Und dann am besten mal den ARC limitieren. Nach Faustformel braucht der ARC 4GB + 1GB RAM je 1TB Rohkapazität der Laufwerke wenn du keine Deduplikation nutzen willst. Demnach bräuchtest du eigentlich 16GB RAM alleine für den ARC aber ich würde vermuten, dass da 8 GB auch reichen würden. Müsstest...

I am using my magic crystal ball and can see you have a raidz based zfs pool I also can see in there that the default ZVOL blocksize of 8k is used. If that's wrong, my crystal ball needs re-calibration. If it is true you need to create the zvol with a larger block size (64k, 128k) to avoid...

Most of the time its the opposite. People loose capaticity if they use raidz and they don't increase the volblocksize first. Sure. If you dont't need a higher volblocksize because of padding overhead a raidz would produce, it is better to keep the volblocksize as small as possible. Otherwise...

Wow, very detailed info here. Took some time to digest it and search more info around to try to understand it the best I can. In a future that I move on to 4k LBA HDD disks, maybe I'll choose to create a new zpool with proper ashift settings and move data over there. But for now I think I'm...

It will be much higher internally. To write something SSDs will need to erase a complete row of cells and and write it again to store a minimal change. So SSDs can read single cells but only modify big rows of cells. So it could be that a row of some hundreds of KB or even some MB need to be...

Nein, volblocksize gilt nur für zvols, also die virtuellen Festplatten der VMs. Bei LXCs werden Datasets genutzt, die haben keine volblocksize sondern sondern eine recordsize. Die scheint aber standardmäßig auf 128K zu sein, also hoch genug, dass da ein raidz keinen Platz durch Padding verschwendet.

Danke für die extrem ausführliche Antwort. Prinzipiell ist das System darauf ausgelegt Server für private Zwecke zu hosten. (Hausautomatisierung, Nextcloud, dhcp, DNS usw..) Mit Ausnahme der Nextcloud also nicht für große Mengen Daten. Ich gehe aktuell davon aus das ich alle 2-3 Jahre eine...

Hello, I have been running two different setups of ZFS Pools with Proxmox and VMs on them. Raid-z2 (6 disks, ashift=12, volblocksize=64k) <-- Virtualdisk (reports blocksize as 512 in VM) <-- NTFS/Ext4 (blocksize 4k) Mirror (6 disks, ashift=12, volblocksize=8k (default)) <--...