Re: ZFS performance (was: Re: deduplicating file systems: VDO withDebian?)
On Thu, 2022-11-10 at 02:19 -0500, gene heskett wrote:
> On 11/10/22 00:37, David Christensen wrote:
> > On 11/9/22 00:24, hw wrote:
> > > On Tue, 2022-11-08 at 17:30 -0800, David Christensen wrote:
>
> [...]
> Which brings up another suggestion in two parts:
>
> 1: use amanda, with tar and compression to reduce the size of the
> backups. And use a backup cycle of a week or 2 because amanda will if
> advancing a level, only backup that which has been changed since the
> last backup. On a quiet system, a level 3 backup for a 50gb network of
> several machines can be under 100 megs. More on a busy system of course.
> Amanda keeps track of all that automatically.
Amanda is nice, yet quite unwieldy (try to get a file out of the backups ...).
I used it long time ago (with tapes) and I'd have to remember or re-learn how to
use amanda to back up particular directories and such ...
I think I might be better off learning more about snapshots.
> 2: As disks fail, replace them with SSD's which use much less power than
> spinning rust. And they are typically 5x faster than commodity spinning
> rust.
Is this a joke?
https://www.dell.com/en-us/shop/visiontek-16tb-class-qlc-7mm-25-ssd/apd/ab329068/storage-drives-media
Cool, 30% discount on black friday saves you $2280 for every pair of disks, and
it even starts right now. (Do they really mean that? What if I had a datacenter
and ordered 512 or so of them? I'd save almost $1.2 million, what a great
deal!)
And mind you, SSDs are *designed to fail* the sooner the more data you write to
them. They have their uses, maybe even for storage if you're so desperate, but
not for backup storage.
> Here, and historically with spinning rust, backing up 5 machines, at 3am
> every morning is around 10gb total and under 45 minutes. This includes
> the level 0's it does by self adjusting the schedule to spread the level
> 0's, AKA the fulls, out over the backup cycle so the amount of storage
> used for any one backup run is fairly consistent.
That's almost half a month for 4TB. Why does it take so long?
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