Virtualized Windows I/O performance on Xen with and without the optimized PV drivers, and versus the Linux host

One of my readers, Randall Ehren, was kind enough to provide benchmarks for Xen-virtualized Windows 2003 and XP with and without the optimized PV driver, and also compare to the underlying host. Most of the text below is copied verbatim from his correspondence with me, I just added some clarification in places.

physical machine description:
dell poweredge r200 server, 8GB ram, 2x250GB SATA 7200rpm in a RAID1

Xen host: ubuntu 8.0.4 LTS Server edition running xen 3.2 hypervisor (this is referred to as the dom0 machine)

This server is hosting two virtual servers (1 – windows 2003 server (1GB RAM), 2 – windows xp (1GB RAM)) and I performed two postmark benchmarks – one with an out of the box windows installation (indicated by “no PV drivers”), the other with a paravirtualized disk driver (indicated by “with Xen PV 0.9.6 drivers”) whose purpose is to greatly increase disk & network performance for windows-based virtual machines running under Xen. the drivers can be found here:

 http://wiki.xensource.com/xenwiki/XenWindowsGplPv

Postmark settings:

set number 10000
set transactions 20000
set subdirectories 5
set size 500 100000
set read 4096
set write 4096

Underlying host

##
## server: ubu 8 amd64 / iron / ext3fs on LVM2

## storage: direct attached / raid1 / 2x250g 7.2k sata / idle
##

Linux vm5 2.6.24-17-xen #1 SMP Thu May 1 15:55:31 UTC 2008 x86_64 GNU/Linux

Time:

        73 seconds total
        59 seconds of transactions (338 per second)

Files:
        20092 created (275 per second)
                Creation alone: 10000 files (10000 per second)
                Mixed with transactions: 10092 files (171 per second)
        9935 read (168 per second)
        10064 appended (170 per second)
        20092 deleted (275 per second)
                Deletion alone: 10184 files (783 per second)
                Mixed with transactions: 9908 files (167 per second)

Data:
        548.25 megabytes read (7.51 megabytes per second)
        1158.00 megabytes written (15.86 megabytes per second)

## server: w2k3 32bit / xen 3.2 / ntfs (no PV drivers)

## storage: direct attached / raid1 / 2x250g 7.2k sata / idle
## xen notes: using ‘tap:aio’ file driver for windows 2003 server “drive”

Time:

        193 seconds total
        123 seconds of transactions (162 per second)

Files:
        20092 created (104 per second)
                Creation alone: 10000 files (166 per second)
                Mixed with transactions: 10092 files (82 per second)
        9935 read (80 per second)
        10064 appended (81 per second)
        20092 deleted (104 per second)
                Deletion alone: 10184 files (1018 per second)
                Mixed with transactions: 9908 files (80 per second)

Data:
        548.25 megabytes read (2.84 megabytes per second)
        1158.00 megabytes written (6.00 megabytes per second)

## server: w2k3 32bit / xen 3.2 / ntfs (with Xen PV 0.9.6 drivers)
## storage: direct attached / raid1 / 2x250g 7.2k sata / idle
## xen notes: using ‘tap:aio’ file driver for windows 2003 server “drive”

Time:

        129 seconds total
        68 seconds of transactions (294 per second)

Files:
        20092 created (155 per second)
                Creation alone: 10000 files (204 per second)
                Mixed with transactions: 10092 files (148 per second)
        9935 read (146 per second)
        10064 appended (148 per second)
        20092 deleted (155 per second)
                Deletion alone: 10184 files (848 per second)
                Mixed with transactions: 9908 files (145 per second)

Data:
        548.25 megabytes read (4.25 megabytes per second)
        1158.00 megabytes written (8.98 megabytes per second)

## server: winxp 32bit / xen 3.2 / ntfs (no PV drivers)

## storage: direct attached / raid1 / 2x250g 7.2k sata / idle
## xen notes: using ‘tap:aio’ file driver for windows xp “drive”

Time:

        336 seconds total
        274 seconds of transactions (72 per second)

Files:
        20092 created (59 per second)
                Creation alone: 10000 files (178 per second)
                Mixed with transactions: 10092 files (36 per second)
        9935 read (36 per second)
        10064 appended (36 per second)
        20092 deleted (59 per second)
                Deletion alone: 10184 files (1697 per second)
                Mixed with transactions: 9908 files (36 per second)

Data:
        548.25 megabytes read (1.63 megabytes per second)
        1158.00 megabytes written (3.45 megabytes per second)

## server: winxp 32bit / xen 3.2 / ntfs (with Xen PV 0.9.6 drivers)
## storage: direct attached / raid1 / 2x250g 7.2k sata / idle
## xen notes: using ‘tap:aio’ file driver for windows xp “drive”

Time:

        233 seconds total
        181 seconds of transactions (110 per second)

Files:
        20092 created (86 per second)
                Creation alone: 10000 files (222 per second)
                Mixed with transactions: 10092 files (55 per second)
        9935 read (54 per second)
        10064 appended (55 per second)
        20092 deleted (86 per second)
                Deletion alone: 10184 files (1454 per second)
                Mixed with transactions: 9908 files (54 per second)

Data:
        548.25 megabytes read (2.35 megabytes per second)
        1158.00 megabytes written (4.97 megabytes per second)

 

Conclusion: seems that the PV driver does help greatly with I/O performance. Of course, comparing to the performance of the underlying host the VMs suck. I’d like to see Randall run the test and use the same box to run at least 2003 in native mode and then post, that should give a great comparison between NTFS and ext3.

Randall/D

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