Re: Desperate with 870 QVO and ZFS

One perhaps important note!! 

When this happens... almost all processes appear in top in the following
state: 

txg state or 

txg-> 

bio.... 

perhaps should the the vfs.zfs.dirty_data_max, vfs.zfs.txg.timeout,
vfs.zfs.vdev.async_write_active_max_dirty_percent be increased,
decreased.... I'm afraid of doing some chage ana finally ending up with
an inestable server.... I'm not an expert in handling these values.... 

Any recommendation?. 

Best regards,

El 2022-04-06 16:36, egoitz@ramattack.net escribió:

> ATENCION: Este correo se ha enviado desde fuera de la organización. No pinche en los enlaces ni abra los adjuntos a no ser que reconozca el remitente y sepa que el contenido es seguro.
> 
> Hi Rainer! 
> 
> Thank you so much for your help :) :) 
> 
> Well I assume they are in a datacenter and should not be a power outage.... 
> 
> About dataset size... yes... our ones are big... they can be 3-4 TB easily each dataset..... 
> 
> We bought them, because as they are for mailboxes and mailboxes grow and grow.... for having space for hosting them... 
> 
> We knew they had some speed issues, but those speed issues, we thought (as Samsung explains in the QVO site) they started after exceeding the speeding buffer this disks have. We though that meanwhile you didn't exceed it's capacity (the capacity of the speeding buffer) no speed problem arises. Perhaps we were wrong?. 
> 
> Best regards, 
> 
> El 2022-04-06 14:56, Rainer Duffner escribió: 
> 
> Am 06.04.2022 um 13:15 schrieb egoitz@ramattack.net: 
> I don't really know if, perhaps the QVO technology could be the guilty here.... because... they say are desktop computers disks... but later. 
> 
> Yeah, they are. 
> 
> Most likely, they don't have some sort of super-cap. 
> 
> A power-failure might totally toast the filesystem. 
> 
> These disks are - IMO -  designed to accelerate read-operations. Their sustained write-performance is usually mediocre, at best. 
> 
> They might work well for small data-sets - because that is really written to some cache and the firmware just claims it's „written", but once the data-set becomes big enough, they are about as fast as a fast SATA-disk. 
> 
> https://www.tomshardware.com/reviews/samsung-970-evo-plus-ssd,5608.html