 Home |
Products |
Support |
Community |
News |
xen-users
[Xen-users] xen 3.3 -> tap:aio performance over nfs
| To: | xen-users@xxxxxxxxxxxxxxxxxxx |
|---|---|
| Subject: | [Xen-users] xen 3.3 -> tap:aio performance over nfs |
| From: | C V <rayvittal-lists@xxxxxxxxx> |
| Date: | Fri, 30 Jan 2009 18:04:47 -0800 (PST) |
| Delivery-date: | Fri, 30 Jan 2009 18:05:30 -0800 |
| Domainkey-signature: | a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=X-YMail-OSG:Received:X-Mailer:Date:From:Subject:To:MIME-Version:Content-Type:Message-ID; b=o/SL3LMcbNzoSUudYbhBiv8flyZ0+dPioAUX/WKu564ZVw2VOkhWT9oVXL8h419RNMEmZ29mKV5wJ6KdNHMrqg1hd1LOB1dGAn7zRoevbgA4gv/6j1KoeN8q4cv2dkLVFFTC1Gb1XnIYuM8K4jb1rJCQd9aW8nJpewpgjjlU5I4=; |
| Envelope-to: | www-data@xxxxxxxxxxxxxxxxxxx |
| List-help: | <mailto:xen-users-request@lists.xensource.com?subject=help> |
| List-id: | Xen user discussion <xen-users.lists.xensource.com> |
| List-post: | <mailto:xen-users@lists.xensource.com> |
| List-subscribe: | <http://lists.xensource.com/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=subscribe> |
| List-unsubscribe: | <http://lists.xensource.com/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=unsubscribe> |
| Sender: | xen-users-bounces@xxxxxxxxxxxxxxxxxxx |
I've been getting disappointing performance for file-backed disks mounted using tap:aio over an NFS mount. For example, bonnie++ reports 3 MB/s for block writes in the domU to that disk, but in dom0, bonnie++ reports 38 MB/s for that same mount. The same domU can get 40 MB/s to the same filer using a phy: block device over iSCSI . It seems that 1. tap:aio causes synchronous writes to the nfs mount (6 writes, wait for ack, write 6 more etc) as opposed to NFSv3 async write 2. Each synchronous write writes very small blocks (4K bytes vs max of 32K bytes) Is there any configuration option to tweak this behavior to get better-performing async writes to the filer? Thanks -- CV _______________________________________________ Xen-users mailing list Xen-users@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-users |
| <Prev in Thread] | Current Thread | [Next in Thread> |
|---|---|---|
| ||
| Previous by Date: | Re: [Xen-users] pygrub CentOS domU - unable to mount lvm partition form dom0 -, Peter Braun |
|---|---|
| Next by Date: | RE: [Xen-users] xen 3.3 -> tap:aio performance over nfs, James Harper |
| Previous by Thread: | [Xen-users] Can't discover DHCP address of domU - can't find VNC console, either, Mike O'Brien |
| Next by Thread: | RE: [Xen-users] xen 3.3 -> tap:aio performance over nfs, James Harper |
| Indexes: | [Date] [Thread] [Top] [All Lists] |
