Search results for query: padding overhead

Thats because of padding overhead. You need to increase the volblocksize from 8K to something like 32K. Otherwise you will loose 50% of your raw capacity (20% parity overhead loss + 30% padding overhead loss). In other words...everything written to a zvol will consume 160% space. You can change...

...https://forum.proxmox.com/threads/abysmal-ceph-write-performance.84361/ Search this forum for "padding overhead". I explained that lot of times. Here is a good article written by the ZFS head developer that explains it down to the block level...

Thank you, for your answer. So, as a first precision, this is just a homelab mainly to learn and have fun, no entreprise service at all. Yes, I am aware of it and will only store data that I can lost on these (and I have an old syno NAS to backup things). That is why I have the main pool in...

...raidz1 and you probably didn't increased your volblocksize from 8K to 16K. In that case VMs will waste alot of space because of padding overhead. 5.) I really would recommend to add disks by using the "/dev/disk/by-id/Yourdisk" and not "/dev/YourDisk". Makes it much easier to identify the...

...on the PVE host. You can also use compression with ZFS on PVE, but that won't help much. You still got the problem of either padding overhead or very big blocksizes. Any kind of raidz1/2/3 or draid just isn't great if you want to run VMs on it (and especialy database VMs). Best would be to...

Friend you helped me pacas I was seeing here in one that only left the 50% as you said and did not understand. The other I did a raidzO even after I did the replication more this congests the network well. I appreciate the help and congratulations for the knowledge! I will try to apply what you...

...SSDs in a raidz1 with ashift=12. When writing 4TB to zvols (your VMs virtual disks) it will also write 2TB of parity data and 2TB of padding overhead. So only 50% of your disks are usable and that is the same as using a striped mirror. And a striped mirror of 4 disks would be a better option...

...two PBS servers? 4 disk raidz1 is bad for MySQL as you would need to use a volblocksize of atleast 32K (in case of ashift=12) to not loose alot of capacity to padding overhead. And MySQL is sync writing with 16K blocks and writing with lower blocksizes to higher blocksizes is always problematic.

...volblocksize - - root@prodcloud02:~# If I understand correctly to remove the lost space in padding overhead on my servers. I need to: Change Block size to 16K on the ZFS storage configuration. For each VM: Disable the replication on the VM Destroy the VM disk on the replication...

...raw capacity because of parity. But because your volblocksize is too small you loose an additional 17% of your raw capacity due to padding overhead. In other word: Everything you write to a zvol should be 133% in size, because for every 1GB of data there is 333MB of padding overhead that...

...an striped mirror (raid10). On paper it will look like you got more space but all the additional space you got is wasted because of padding overhead. Then everything will be something like 133%, 150% or 166% in size. You really should read the links I posted above. Especially...

...here (in "CODE"-Tags from the formatting toolbar). Additionally you should definitely read some of the posts Dunuin mentioned - he has done a very fine job with detailed explanations regarding the mentioned "padding overhead" and the "much more space used than expected"-effect. Best regards

I explained it atleast 100 times in this forum. Search this forum for "padding overhead". You probably need to destroy and recreate all zvols with a bigger volblocksize so your raidz1/2/3 isn't wasting too much space because of padding overhead. If you want to understand the padding overhead...

When using raidz there is padding overhead when using zvols with a too small volblocksize. Using the default volblocksize of 8K you will loose 50% of your raw capacity, so only 4 of 8 drives capacity will be usable. 12TB you will loose for parity, 36TB you will loose to padding overhead and only...

And beside not working discard/trim the padding overhead of a raidz1/2/3 could also increase the size when using a too low volblocksize. But paddin overhead alone shouldn't be more than 200%.

Awesome thanks for the detailed response! I think i will use VMs for the seedbox and media server and most of the other services as well that are internet facing to make them more isolated and allow me to directly mount SMB/NFS. That being said, in my case the media server is sent through a...

Thats because of padding overhead. See this article that describes it: https://www.delphix.com/blog/delphix-engineering/zfs-raidz-stripe-width-or-how-i-learned-stop-worrying-and-love-raidz With a 6 disk raidz1 using ashift=12 (ZFS will use 4K as the smallest block/sector size it can write to a...

...wouldn't use raidz1 as a VM/LXC storage if you don't really require all that capacity. Read this article explaining volblocksize and padding overhead: https://www.delphix.com/blog/delphix-engineering/zfs-raidz-stripe-width-or-how-i-learned-stop-worrying-and-love-raidz Using 8x SSDs in a...

Ok that would be sufficient enough at first place. So I was trying to make everything (at least theoretically) 1:1. wIth an OS doing read/writes at 4k (possibly you could change that somehow but I don t care to go that direction) we need the underlaying storage to use 4k blocks as well. With...

...disk. If you read https://www.delphix.com/blog/delphi...or-how-i-learned-stop-worrying-and-love-raidz by now you will see that padding overhead will be a result of a bad relation of volblocksize, ashift and your numbers of databearing disks. So its no problem to go from ashift 9 to ashift...