[pve-devel] [PATCH pve-doc 2/5] ZFS RAM usage more precise.

[Wolfgang Link]

Who as an 1TB l2arc?
and yes if you enable Dedub you need additional 320Bytes per Block.
This is only an approximately Ram usage where user can calculate.

On 10/04/2016 08:51 AM, Alexandre DERUMIER wrote:
>>> +ZFS uses a lot of memory, a good calculation is 4GB plus 1GB RAM
>>> +for each TB RAW disk space if you want to use ZFS.
> 
> also, if l2arc is enabled, zfs take 240 bytes memory for each block in l2arc.
> if you use small block (4k) for your pool for example, this can be very huge (64GB memory for 1TB)
> 
> 
> 
> ----- Mail original -----
> De: "Wolfgang Link" <w.link at proxmox.com>
> À: "pve-devel" <pve-devel at pve.proxmox.com>
> Envoyé: Lundi 3 Octobre 2016 09:28:56
> Objet: [pve-devel] [PATCH pve-doc 2/5] ZFS RAM usage more precise.
> 
> --- 
> pve-installation.adoc | 4 ++-- 
> 1 file changed, 2 insertions(+), 2 deletions(-) 
> 
> diff --git a/pve-installation.adoc b/pve-installation.adoc 
> index 032fd51..485f077 100644 
> --- a/pve-installation.adoc 
> +++ b/pve-installation.adoc 
> @@ -135,8 +135,8 @@ required for lvmthin snapshots). 
> ZFS Performance Tips 
> ^^^^^^^^^^^^^^^^^^^^ 
> 
> -ZFS uses a lot of memory, so it is best to add additional 8-16GB RAM 
> -if you want to use ZFS. 
> +ZFS uses a lot of memory, a good calculation is 4GB plus 1GB RAM 
> +for each TB RAW disk space if you want to use ZFS. 
> 
> ZFS also provides the feature to use a fast SSD drive as write cache. The 
> write cache is called the ZFS Intent Log (ZIL). You can add that after 
>