RE: [EXTERNAL] Re: Garbage Collector

["Durity, Sean R" <SE...@homedepot.com>]

My default is G1GC using 50% of available RAM (so typically a minimum of 16 GB for the JVM). That has worked in just about every case I’m familiar with. In the old days we used CMS, but tuning that beast is a black art with few wizards available (though several on this mailing list). Today, I just don’t see GC issues – unless there is a bad query in play. For me, the data model/query construction is the more fruitful path to achieving performance and reliability.



Sean Durity

From: Jon Haddad <jo...@jonhaddad.com>
Sent: Tuesday, March 19, 2019 2:16 PM
To: user@cassandra.apache.org
Subject: [EXTERNAL] Re: Garbage Collector

G1 is optimized for high throughput with higher pause times.  It's great if you have mixed / unpredictable workloads, and as Elliott mentioned is mostly set & forget.

ZGC requires Java 11, which is only supported on trunk.  I plan on messing with it soon, but I haven't had time yet.  We'll share the results on our blog (TLP) when we get to it.

Jon

On Tue, Mar 19, 2019 at 10:12 AM Elliott Sims <el...@backblaze.com>> wrote:
I use G1, and I think it's actually the default now for newer Cassandra versions.  For G1, I've done very little custom config/tuning.  I increased heap to 16GB (out of 64GB physical), but most of the rest is at or near default.  For the most part, it's been "feed it more RAM, and it works" compared to CMS's "lower overhead, works great until it doesn't" and dozens of knobs.
I haven't tried ZGC yet, but anecdotally I've heard that it doesn't really match or beat G1 quite yet.

On Tue, Mar 19, 2019 at 9:44 AM Ahmed Eljami <ah...@gmail.com>> wrote:
Hi Folks,

Does someone use G1 GC or ZGC on production?

Can you share your feedback, the configuration used if it's possible ?

Thanks.


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Re: [EXTERNAL] Re: Garbage Collector

[Ahmed Eljami <ah...@gmail.com>]

Thx guys for sharing your experiences with G1.

Since I sent you my question about GC, we have updated the version of java.
Always with CMS/java8 and updating from u9x to u201. Just with that, we
observe a gain of 66% (150ms ==> 50ms of STW).... :)

We are planning a second tuning, this time with G1.

Thanks.

Le mar. 19 mars 2019 à 19:56, Durity, Sean R <SE...@homedepot.com>
a écrit :

> My default is G1GC using 50% of available RAM (so typically a minimum of
> 16 GB for the JVM). That has worked in just about every case I’m familiar
> with. In the old days we used CMS, but tuning that beast is a black art
> with few wizards available (though several on this mailing list). Today, I
> just don’t see GC issues – unless there is a bad query in play. For me, the
> data model/query construction is the more fruitful path to achieving
> performance and reliability.
>
>
>
> Sean Durity
>
>
>
> *From:* Jon Haddad <jo...@jonhaddad.com>
> *Sent:* Tuesday, March 19, 2019 2:16 PM
> *To:* user@cassandra.apache.org
> *Subject:* [EXTERNAL] Re: Garbage Collector
>
>
>
> G1 is optimized for high throughput with higher pause times.  It's great
> if you have mixed / unpredictable workloads, and as Elliott mentioned is
> mostly set & forget.
>
>
>
> ZGC requires Java 11, which is only supported on trunk.  I plan on messing
> with it soon, but I haven't had time yet.  We'll share the results on our
> blog (TLP) when we get to it.
>
>
>
> Jon
>
>
>
> On Tue, Mar 19, 2019 at 10:12 AM Elliott Sims <el...@backblaze.com>
> wrote:
>
> I use G1, and I think it's actually the default now for newer Cassandra
> versions.  For G1, I've done very little custom config/tuning.  I increased
> heap to 16GB (out of 64GB physical), but most of the rest is at or near
> default.  For the most part, it's been "feed it more RAM, and it works"
> compared to CMS's "lower overhead, works great until it doesn't" and dozens
> of knobs.
>
> I haven't tried ZGC yet, but anecdotally I've heard that it doesn't really
> match or beat G1 quite yet.
>
>
>
> On Tue, Mar 19, 2019 at 9:44 AM Ahmed Eljami <ah...@gmail.com>
> wrote:
>
> Hi Folks,
>
>
>
> Does someone use G1 GC or ZGC on production?
>
>
>
> Can you share your feedback, the configuration used if it's possible ?
>
>
>
> Thanks.
>
>
>
>
> ------------------------------
>
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> privileged. It is intended solely for the addressee. Access to this Email
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> disclosure, copying, distribution or any action taken or omitted to be
> taken in reliance on it, is prohibited and may be unlawful. When addressed
> to our clients any opinions or advice contained in this Email are subject
> to the terms and conditions expressed in any applicable governing The Home
> Depot terms of business or client engagement letter. The Home Depot
> disclaims all responsibility and liability for the accuracy and content of
> this attachment and for any damages or losses arising from any
> inaccuracies, errors, viruses, e.g., worms, trojan horses, etc., or other
> items of a destructive nature, which may be contained in this attachment
> and shall not be liable for direct, indirect, consequential or special
> damages in connection with this e-mail message or its attachment.
>


-- 
Cordialement;

Ahmed ELJAMI