All of lore.kernel.org
 help / color / mirror / Atom feed
From: Wodkowski, PawelX <pawelx.wodkowski at intel.com>
To: spdk@lists.01.org
Subject: Re: [SPDK] vhost target failover?
Date: Mon, 16 Apr 2018 08:47:21 +0000	[thread overview]
Message-ID: <F6F2A6264E145F47A18AB6DF8E87425D7011EE3D@IRSMSX102.ger.corp.intel.com> (raw)
In-Reply-To: CY4PR1601MB12051A14D1FA7C3BE6977F0BA6B00@CY4PR1601MB1205.namprd16.prod.outlook.com

[-- Attachment #1: Type: text/plain, Size: 2148 bytes --]

We can implement any kind of failover mechanism. Starting some kind of proxy process to pass vhost user messages to child process would not be so hard to implement. In theory.
But the question is how to handle crash in the middle of request? In virtio-net situation is much simpler - if TCP network packet is lost it will be retransmitted. If packet is retransmitted after vhost-net target restart - it will be filtered by TCP layer. What to do if in the middle of eg 2MB write vhost crashes and restarts? One solution could be to promote the vhost target restart/recover to the SCSI reset event. It's doable.

Another issue is that if vhost crashes it mean there was some serious issue including possibility of trashing guest memory. Personally, I recommend (and I think DPDK recommend this also) to save what you can and restart everything.

Adding Jim as he could write something more here.

Pawel

From: SPDK [mailto:spdk-bounces(a)lists.01.org] On Behalf Of Huang Frank
Sent: Monday, April 16, 2018 10:09 AM
To: spdk <spdk(a)lists.01.org>
Subject: Re: [SPDK] vhost target failover?

hi, Pawel

Thanks.
Is there any  suggestions for this issue? Or any plans to provide High Availability of vhost target in the future?

________________________________
kinzent(a)hotmail.com<mailto:kinzent(a)hotmail.com>

From: Wodkowski, PawelX<mailto:pawelx.wodkowski(a)intel.com>
Date: 2018-04-16 16:02
To: Storage Performance Development Kit<mailto:spdk(a)lists.01.org>
Subject: Re: [SPDK] vhost target failover?
There is none currently. Device will be seen as dead. All requests will stuck. Anything else related to guest should be unaffected.

Pawel

From: SPDK [mailto:spdk-bounces(a)lists.01.org] On Behalf Of Huang Frank
Sent: Monday, April 16, 2018 9:42 AM
To: spdk <spdk(a)lists.01.org<mailto:spdk(a)lists.01.org>>
Subject: [SPDK] vhost target failover?

Hi，all

What's the failover mechism of vhost target? If the vhost target goes to crash, how to make sure the guest can process without affectting?

Thanks,
Frank.

________________________________
kinzent(a)hotmail.com<mailto:kinzent(a)hotmail.com>

[-- Attachment #2: attachment.html --]
[-- Type: text/html, Size: 13743 bytes --]

             reply	other threads:[~2018-04-16  8:47 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-16  8:47 Wodkowski, PawelX [this message]
  -- strict thread matches above, loose matches on Subject: below --
2018-04-18 16:29 [SPDK] vhost target failover? Ming Lin
2018-04-17  1:55 Huang Frank
2018-04-16 23:41 Luse, Paul E
2018-04-16 23:40 Ming Lin
2018-04-16 23:19 Luse, Paul E
2018-04-16 23:14 Ming Lin
2018-04-16 19:37 Harris, James R
2018-04-16  8:08 Huang Frank
2018-04-16  8:02 Wodkowski, PawelX
2018-04-16  7:41 Huang Frank

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=F6F2A6264E145F47A18AB6DF8E87425D7011EE3D@IRSMSX102.ger.corp.intel.com \
    --to=spdk@lists.01.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.