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Subject: Re: TRIM, iSCSI and %busy waves
To: freebsd-stable@freebsd.org
References: <92b92a3d-3262-c006-ed5a-dc2f9f4a5cb9@zhegan.in>
 <2daf0677-3feb-6c4c-38d3-ed552f1a3cf0@multiplay.co.uk>
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From: "Eugene M. Zheganin" <emz@norma.perm.ru>
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Date: Sat, 7 Apr 2018 11:19:06 +0500
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Hi,

05.04.2018 20:15, Eugene M. Zheganin wrote:
>
>> You can indeed tune things here are the relevant sysctls:
>> sysctl -a | grep trim |grep -v kstat
>> vfs.zfs.trim.max_interval: 1
>> vfs.zfs.trim.timeout: 30
>> vfs.zfs.trim.txg_delay: 32
>> vfs.zfs.trim.enabled: 1
>> vfs.zfs.vdev.trim_max_pending: 10000
>> vfs.zfs.vdev.trim_max_active: 64
>> vfs.zfs.vdev.trim_min_active: 1
>> vfs.zfs.vdev.trim_on_init: 1
>>
> Well, I've already seen these. How do I tune them ? The idea of just 
> tampering with them and seeing what will happen doesn't look like a 
> bright one to me. Do I increase or decrease them ? Which ones do I 
> have to avoid ?
>
So, about these - are there any best practices to fine-tune them ? How 
do you tune them (I won't blame anyone for examples) ?  Or are they 
"just there" and nobody touches them ?

Thanks.
Eugene.