Re: 答复: Re: Help：Can xen restore several snapshots more faster at same time？

[Wei Liu <wei.liu2@citrix.com>]

Please avoid top-posting.

On Mon, Nov 13, 2017 at 08:25:16AM +0000, Chenjia (C) wrote:
> 1.       is there some way to improve the xenstored process performance?
> 

The latest version of Cxenstored and Oxenstored have improved
transaction handling. Not sure which version you're using.

> 2.       We also try the virsh tool to restore several xen at same
> time ,we fount the virsh can restore 40+ snapshot(1G per snapshot) at
> same time, the performance is good when snapshot is all in ramdisk.
> But we can’t let all the snapshot is always in ramdisk for it is too
> big. Is there some way to reduce these virsh snapshots space?(these
> snapshot is same: same OS, same config, but need with different IP
> address)

For libvirt question you need to ask on libvirt list.

> 
> Would you please offer us some feedback? Thanks.
> By the way, can we talk with Chinese if possible?

Sorry but communication on mailing list needs to be in English so other
people can join the discussion and / or provide suggestions.

> 
> 发件人: HUANG SHENGQIANG
> 发送时间: 2017年11月6日 18:32
> 收件人: Chenjia (C) <chenjia09@huawei.com<mailto:chenjia09@huawei.com>>
> 主题: FW: Re: [Xen-devel] Help：Can xen restore several snapshots more faster at same time？
> 
> --------------------------------------------------
> HUANG SHENGQIANG HUANG SHENGQIANG
> M: +86-18201587800<tel:+86-18201587800>(优先)/+1-6046180423<tel:+1-6046180423>(海外出差)
> E: huang.shengqiang@huawei.com<mailto:huang.shengqiang@huawei.com>
> 产品与解决方案-交换机与企业网关解决方案架构与设计部
> Products & Solutions-Switch & Enterprise Gateway Solution Architecture & Design Dept
> From:Wei Liu
> To:HUANG SHENGQIANG,
> Cc:xen-devel@lists.xenproject.org,Wangjianbing,Wei Liu,
> Date:2017-11-06 18:28:58
> Subject:Re: [Xen-devel] Help：Can xen restore several snapshots more faster at same time？
> 
> On Mon, Nov 06, 2017 at 04:38:51AM +0000, HUANG SHENGQIANG wrote:
> > Dear XEN expert,
> >
> > I find a blocker issue in my project. Would you please offer us some feedback?
> >
> > The description from my development team:
> > we need restore as much as xen snapshot at same times, but we found ‘xl restore’ command is work linearly,  if we want to restore a new xen snapshot, we need to wait for the previous snapshot finish it’s work. We try to debug the xl source ,we found the follow information:
> > [cid:image001.png@01D356F6.B8EE87E0]
> >
> 
> Please don't send pictures.
> 
> > When an snapshot is being restore, we can see another process is blocked.  We trying to delete the acquire_lock from the source code , then we see all the snapshots are being restore at same time, but restore is still very slow, one snapshot needs about 25 seconds  to finish restore(our environment is cpu E52620,  256G memory, SSD hard disk. The snapshot is Win7 OS with 2G memory).
> >
> 
> There is a lock in xl as you can see in the stack trace.
> 
> > So , does xen have the way to restore more faster when several snapshot is restore at same time? Why KVM can restore several snapshot fast at same time? (We try the same experiment in KVM, we got we can restore about 50+ snapshot in 20S. )
> >
> 
> Part of the toolstack needs to be reworked. You can start by removing
> the lock in xl to see what breaks.

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