[oi-dev] Improving file transfer speed on ZFS

[Toomas Soome]

> On 4. Nov 2025, at 09:06, Stephan Althaus via oi-dev <oi-dev at openindiana.org> wrote:
> 
> On 11/4/25 05:03, Atiq Rahman wrote:
>> Hi,
>> When I am copying over files to the zfs dataset on an external HDD, the speed is one third of what it is over exFAT. This is zfs to zfs copy which is basically way slower than zfs to exFAT.
>> 
>> This was my zpool create command on the external drive,
>> 
>> ```
>> zpool create -o ashift=12 -O compression=lz4 -o autotrim=off -O mountpoint=none -O atime=off -O dnodesize=auto hyperspace /dev/dsk/c4t0d0
>> ```
>> 
>> And, this is how the dataset was created:
>> 
>> ```
>> zfs create -o recordsize=1M -o normalization=formD -O mountpoint=/media hyperspace/media
>> ```
>> 
>> I know zfs has journaling overhead. But, is it possible to set certain zfs properties to improve the transfer speed?
>> 
>> 
>> Best! <>
>> Atiq <>
>> 
>> _______________________________________________
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> Hello Atiq!
> 
> How do you copy, please show the commands (?)
> 
> You may want to investigate the read speed with something like zfs send ... > /dev/null
> 
> If you do a zfs send -> receive, a buffer like "mbuffer" may help, over network pathes in combination with a compression pbzip2, pigz ...
> 
> 
> 
> Regards,
> 
> Stephan
> 
If its external HDD, which interface? usb3?

rgds,
toomas


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