OT: XP SP2 Security Hole / Backup Thread Appended
D. Thomas Podnar
tom at microlite.com
Sun Oct 3 14:32:10 PDT 2004
: Jean-Pierre A. Radley wrote:
: > Transpower at aol.com propounded (on Sun, Oct 03, 2004 at 11:41:11AM
: > -0400):
: >> In a message dated 10/2/2004 9:08:30 PM Eastern Daylight Time,
: >> fp at wjv.com writes:
: >>
: >>> Transpower at aol.com, the prominent pundit, on Sat, Oct 02 11:19
: >>> while half mumbling half-witicized:
: >>>
: >>>> One positive thing about XP SP2:? I installed it several days
: >>>> ago and I must say that my computer (specifically disk reads and
: >>>> writes) appears to be much faster than with SP1.
: >>>
: >>> Appearances can be deceiving. In other words, do you have any
: >>> benchmarks you ran before and after. I do that on disk systems and
: >>> save the results in the Unix servers.
: >>
: >> No benchmarks yet; my demo copy of Performance Test ran out. Next
: >> time I do a backup I'll let you know if there's any difference. By
: >> the way, backing up 13 GB used to take 1 hour, 20 minutes on an HP
: >> Ultrium LTO; after changing settings so that system cache (rather
: >> than programs) is optimized (and setting System Mechanic so that XP
: >> writes the cache every 2 seconds), I got the backup time down to 20
: >> minutes! And shadow copy now works properly.
: >
: > Speaking of backups, on OSR 5.0.7, I've installed a SCSI Iomega REV
: > drive. A complete backup which took 62 minutes to a DDS-4 tape takes
: > 20 minutes to a REV drive.
:
: We have one of those too on our new box but I don't have a way to make a
: good comparison like that.
Yes, you do. See below.
: Old box didn't have dds-4 but dds-3 and the tape was on a 20 or 40mhz scsi
: card while the rev is on udma 100 or 133 IDE.
Not on OpenServer. Not exactly.
: Old box let the tape drive do the compression, new box per-force must do the
: compression in cpu. Old box had a plain 80mhz or u160 scsi drive on a
: ordinary 33mhz x 32bit pci card, new box has a raid-10 array of u320 drives
: spread over 2 u320 channels on a 133mhz x 64bit pci-x card etc etc etc...
:
: It's taking me 3:45 hours to back up and 4:05 to verify 54 gigs.
: which is compressing down to only 17 gigs of raw media space!
:
: ---snip BackupEDGE summary---
: Files Encountered = 757032
: Total Data = 54.48GB
: Data Written = 17.18GB
: Volume Left = 15.40GB
: SW Compression = 76%
: Elapsed Time = 03:47:39
: Data Transfer Speed = 1351477 bytes/sec
: Net Transfer Rate = 77.11 MB/min
: --------
:
: This includes about 4 gigs of jpegs and pngs (scanned documents that are
: already highly compressed)
: and about 42 gigs of customers bacups, mostly in the form of complete rsync
: copies of customers filepro trees (just the menus, config & filepro dir, no
: binaries) and a few sets of compressed tars that revolve every night. The
: tars are bzip2 but the rsync'ed trees are straight fp and very compressible.
:
: What I do have for comparison is the ctar summary from the old box, which
: due to the smaller media had a lot of things excluded from the backup...
: ----snip----
: FILES: 236725
: Total DATA: 8.026Gb (Gigabytes)
: Actual Tape Data Written: 8.185Gb (Gigabytes)
: ROOM LEFT on this Volume: 15.253Gb (Gigabytes)
:
: Elapsed Time: 42 minutes 53 seconds
: Data Transfer Speed: 3420199 bytes/sec ( 195.7 Mb/min)
: ----snip----
:
: I'm almost positive that someone somewhere told me that the rev was faster
: than dat, (I don't remember if it was backupedge or seneca data, or who...)
: but... this shows the old std-9000 drive working twice as fast as the rev.
NO, It DOESN'T!
: So all in all, I'm pretty dissapointed.
You should be ecstatic. I don't think you have interprested the
statistics properly.
: Total Data = 54.48GB
: Data Written = 17.18GB
: Elapsed Time = 03:47:39
First, remember that the CTAR MB/min rating is based on
"uncompressed data over time". In this case, you were using
hardware compression, but the same metric is used when software
compression is running, that is, "the amount of data that would
have been written if I hadn't been compressing it" over time.
BackupEDGE 2.0 uses the actual amount written after compression, over
time. But it has a killer compressor, so it calculated how long it
took to get the 17.18GB it ended up writing, over time.
In very real terms, BackupEDGE on the REV copied 54.48 Gigabytes of
YOUR DATA in 3.89 hours, for roughly 14.005 Gigabytes per hour.
CTAR on tape copied 8.026 Gigabytes in .715 hours, or
roughly 11.225 Gigabytes per hour.
This made your BackupEDGE/REV backup 25 percent faster, NOT counting the
fact that you excluded a bunch of files and have to waste time doing
multiple backups. And it will take you less than 1 second to access and
begin restoring any file on the REV., vs. minutes for the DDS. At your
current compression ratio, you'd get over 100GB on your REV media.
And it cost you a little over $300 bucks.
Now, the BAD news is that, if you are running OpenServer, the "WD"
driver which is running the REV runs in PIO (programmed I/O) mode, not
udma mode. The highest native write performance we see on OpenServer
is around 200MB/min for the REV, while the average rate of a full
SCSI REV (like JP's) is around 1,000MB/min (1,300 at the beginning,
slowing down to around 700 at the end of the media).
If you are running Linux and have DMA enabled on /dev/hdaX (whichever
device node is running the REV), that's different. You're probably
getting very good native write speeds with an ATAPI REV.
Obviously, we recommend SCSI for OpenServer.
The raw write rate of any device is easy to test.
1) Set compression to N in the BackupEDGE resource manager.
2) Create a directory with a couple of 1GB files in it.
(Write enough data so that the startup time of a tape drive
becomes lost in the noise.)
3) Back up just that directory and check the statistics.
This URL provides up-to-date information on running various REV
devices under OpenServer, UnixWare, Linux and AIX...
http://www.microlite.com/REV_Download/rev_download.html
Regards,
Tom
---
D. Thomas Podnar
tom at microlite.com http://www.microlite.com
Microlite Corporation 724-375-6711 Voice
2315 Mill Street 724-375-6908 Fax
Aliquippa PA 15001-2228 888-257-3343 Toll Free Sales
-------------------------------------------------------
Developers of Microlite BackupEDGE
:
: Brian K. White -- brian at aljex.com -- http://www.aljex.com/bkw/
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