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From: Dietmar Maurer <dietmar@proxmox.com>
To: "Proxmox Backup Server development discussion"
	<pbs-devel@lists.proxmox.com>,
	"Fabian Grünbichler" <f.gruenbichler@proxmox.com>
Subject: Re: [pbs-devel] [PATCH proxmox-backup] backup/verify: improve speed by sorting chunks by inode
Date: Wed, 14 Apr 2021 18:44:46 +0200 (CEST)	[thread overview]
Message-ID: <1688290929.3134.1618418686372@webmail.proxmox.com> (raw)

> zfs with single spinner + fast special device, with a (not counted ;)) 
> warmup run and everything fitting into cache:
> 
> Benchmark #1: stock
>   Time (mean ± σ):     21.407 s ±  0.819 s    [User: 20.1 ms, System: 15.2 ms]
>   Range (min … max):   21.070 s … 23.078 s    6 runs
> 
> Benchmark #2: patched
>   Time (mean ± σ):     47.119 s ±  0.018 s    [User: 29.5 ms, System: 15.1 ms]
>   Range (min … max):   47.107 s … 47.154 s    6 runs
> 
> Summary
>   'stock' ran
>     2.20 ± 0.08 times faster than 'patched'

I assume you have about 3000 chunks? On XFS, I can do 3000 stat() calls per second (after cache cleared).
So why the hell are stat calls that slow on ZFS with special device? Or what causes that delay (stat or sort)?




             reply	other threads:[~2021-04-14 16:45 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-14 16:44 Dietmar Maurer [this message]
2021-04-15  7:19 ` Fabian Grünbichler
  -- strict thread matches above, loose matches on Subject: below --
2021-04-14  7:17 Dietmar Maurer
2021-04-13 14:35 Dominik Csapak
2021-04-14 13:24 ` Fabian Grünbichler

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