This test was performed during daily operations. This is usually the time
when you need to do a restore. Therefore, the machine you're trying to
restore won't be the only machine sending packets over the LAN(if you can't
shutdown all of the other servers).
Still, if you can get 14-17GB/hour
If you read the mail, you can see that 1GB was restored in 6 mins. 2 mins
was mounting time, and search on the tape. Hopefully, this doesn't happen
every 8 mins.
So, the throughput is 1GB/6mins, or 10GB per hour.
Still, if you have a machine with 1TB of data, the restore time would be,
in your case 1000/14. This means 71 hours of restoring. Who has the time to
wait this long?
In best case, when you get 17GB/hour, total restore time would be 58 hours.
Does your boss know about this? :)
Best Regards
Daniel sparrman
-----------------------------------
Daniel Sparrman
Daniel Sparrman
Exist i Stockholm AB
Bergkällavägen 31D
192 79 SOLLENTUNA
Växel: 08 - 754 98 00
Mobil: 070 - 399 27 51
<James@AXACS.
COM> To: ADSM-L AT VM.MARIST DOT EDU
Sent by: cc:
"ADSM: Dist Subject: Re: Incremental forever
-- any problems? (Scary thoughts)
Stor Manager"
<ADSM-L AT VM DOT MA
RIST.EDU>
2001-12-18
22:22
Please
respond to
"ADSM: Dist
Stor Manager"
That seems to be really slow 8 gb per hour. I'm running TSM server on a h70
with 100mb ethernet dedicated backbone to my NT clients. These clients are
mostly compaq prolient 7000. I average about 14-17 GB per hour on my
restores. I'm hoping that an upgrade coming soon to gigabit will increase
these speeds.
"Daniel Sparrman" <daniel.sparrman AT EXIST DOT SE>@VM.MARIST.EDU> on 12/18/2001
03:50:44 PM
Please respond to "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
Sent by: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
To: ADSM-L AT VM.MARIST DOT EDU
cc:
Subject: Re: Incremental forever -- any problems? (Scary thoughts)
Hi
One of our customers is running a medium site with 180 servers, with about
10TB of storage.
Their using an IBM 3584 Anaconda with 2 fibre attached drives.
The machine is a IBM P-Series 640, with RAID 1+0.
One of the largest servers is about 700GB. Its the fileserver running user
data and home directories.
Mount time, including search of files on the tape is about 2 min. When
restoring 1GB, the total time is about 8 min. This means That a total
restore of the server would take about 70 hours to complete. This formula
is 2 mins to search and mount tape, 6 mins to restore data.
The customers P-Series machine is equipped with 2 100Mbs Ethernet cards,
and 1 IBM Token-Ring 100Mbs card. The test was on one of the ethernet
cards.
Today, the customer is using OTG DiskXtender. This is for two reasons; one
to save primary diskspace, the other to minimize the amount of data that
has to be restored in an event of disaster.
The LTO drives can perform 15MB/s, or 30MB/s compressed.
The P-Series machine is not the bottleneck. Usually, the network sends
about 3000 packets with a peak at 7000. During backup, 27.000 packets is
sent with a peak at 50.000. According to the communications guys, this is
very high.
The clients is Compaq Proliant machines with about 4GB of memory, two
processors running at Xeon 750(i think).
So, there shouldn't be a bottleneck.
According to the communications guys, the maximum theoretical speed of
100Mbs ethernet is about 12.5MB/s, or running at full duplex, 25MB/s. The
first problem with this is that this is a one way communication(server to
client).
With 12.5MB/s restore time, the total restore of 700GB would take 15 hours.
Who has a primary fileserver that can be down for 15 hours?
And, this is only theoretical.
With 1GB ethernet, the theoretical capacity is about 30MB/s. And this is
only theoretical. The restore would take about 7.5 hours. Whats if this
happend in the morning? Would the users take vacation and come back the
next day?
Just some thoughts....
Best Regards
Daniel Sparrman
-----------------------------------
Daniel Sparrman
Daniel Sparrman
Exist i Stockholm AB
Bergkällavägen 31D
192 79 SOLLENTUNA
Växel: 08 - 754 98 00
Mobil: 070 - 399 27 51
Alex Paschal <AlexPaschal AT FREIGHTLINER DOT COM>
Sent by: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
2001-12-18 11:06 PST
Please respond to "ADSM: Dist Stor Manager"
To: ADSM-L AT VM.MARIST DOT EDU
cc:
bcc:
Subject: Re: Incremental forever -- any problems?
I agree with Wanda. Any kind of modern library and tape technology adds
very little time to the restore. WELL, ok, the costly ones, anyway. My
1TB
NT fileserver (I know, I know) lives on 99 primary pool tapes right now.
Collocate=filespace, so I'll be doing 3 restores at the same time, assuming
even distribution, and assuming every tape must be mounted during the
restore, that's about 33 mounts per filespace, or, assuming a 60 second
mount, an additional half hour due to mounts. I'm willing to bet that's
not
my bottleneck. STK 9840, STK Powderhorn 9310 (6000 slot library), ACSLS 6
(library manager), DTELM 6.1 (external library manager for TSM to talk to)
I can really see no point in doing full backups except to give management a
warm fuzzy and justify buying more network.
How about the rest of you? What mount times are you seeing with your
libraries and how many tapes does your largest box live on? SHOW
VOLUMEUSAGE NODENAME is a quick way to eyeball it. It's an unsupported
command, so I assume no liability if it brings your server down.
Alex Paschal
Storage Administrator
Freightliner, LLC
(503) 745-6850 phone/vmail
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