I have several similarly configured Dell Servers with same slow backups. Running ARCserve 2000 Advanced Edition on Windows 2000 Advanced Server, with backups performed on local machine to Sony AIT3 tape drives. According to specs, the Aic-7899 controller and AIT tape drives should allow for a min of 12MB/sec but the best we get is about 350 MB/min. All firmware and drivers are updated. Now looking at ARCserve. Any suggestions? What else could I look at?
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Slow Backups 3
- Thread starter bizzyb
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Now, I am becoming more curious. If these throughput rates are acceptable, then what does that say about the specs from the various manufacturers?
Am I naive in trying to achieve the quoted rates? This is not meant to be sarcastic. I am puzzled by the responses.
Am I naive in trying to achieve the quoted rates? This is not meant to be sarcastic. I am puzzled by the responses.
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3
- #6
I share the same response as the others...that speed is really pretty good. To shed a little light on why I feel that way, all I can give you is an analogy.
100BaseT is rated at 100Mb/sec, or 10MB/sec. ALL theoretical limits. In the real world if I can get 6-7MB/sec of throughput I am well pleased.
Most manufacturer's performance claims are based on IDEAL (read unrealistic) circumstances and situations that rarely occur in the real world, and should be taken only in comparison to another product. Will my 36GB/hr tape drive do 36GB/hr? Nope. Will my 14.4GB/hr tape drive do 14.4GB/hr? Nope. Will my 36GB/hr tape drive backup the same date in 40% of the time as my 14.4GB/hr? Generally speaking, yep.
I hope this helps you understand the responses you have received to your post.
Regards,
Don Osicky
100BaseT is rated at 100Mb/sec, or 10MB/sec. ALL theoretical limits. In the real world if I can get 6-7MB/sec of throughput I am well pleased.
Most manufacturer's performance claims are based on IDEAL (read unrealistic) circumstances and situations that rarely occur in the real world, and should be taken only in comparison to another product. Will my 36GB/hr tape drive do 36GB/hr? Nope. Will my 14.4GB/hr tape drive do 14.4GB/hr? Nope. Will my 36GB/hr tape drive backup the same date in 40% of the time as my 14.4GB/hr? Generally speaking, yep.
I hope this helps you understand the responses you have received to your post.
Regards,
Don Osicky
Sorry for the typo...
tape drive backup the same date in 40% of ...
should read:
tape drive backup the same data in 40% of ...
Also thought of some things you could check.
Is the compression engaged on the drive? I know that lots of manufacturer specs state X MB/sec with compression and .5X MB/sec native mode.
Also, is the drive starting and stopping? If so, this is an indication that the data is not streaming to the drive, which will impact performance. If the drive is not streaming then the source is not supplying the data fast enough. Sometimes this can be cause by the tape drive being on the same SCSI bus as the drive(s). Also, antivirus software can be interfering with the process...
Just some more thoughts.
Regards,
Don Osicky
tape drive backup the same date in 40% of ...
should read:
tape drive backup the same data in 40% of ...
Also thought of some things you could check.
Is the compression engaged on the drive? I know that lots of manufacturer specs state X MB/sec with compression and .5X MB/sec native mode.
Also, is the drive starting and stopping? If so, this is an indication that the data is not streaming to the drive, which will impact performance. If the drive is not streaming then the source is not supplying the data fast enough. Sometimes this can be cause by the tape drive being on the same SCSI bus as the drive(s). Also, antivirus software can be interfering with the process...
Just some more thoughts.
Regards,
Don Osicky
northstardave
MIS
That brings up a question, then.
My drive starts & stops continually (poweredge 1650, 1G ram (500MB free), Raid5 on Perc, powervault 122T on dedicated scsi card). I've turned off the antivirus, cpu load is typically around 15%, & it's not swapping.
What else can I look for that would impact my streaming performance with Arcserve 2K?
My drive starts & stops continually (poweredge 1650, 1G ram (500MB free), Raid5 on Perc, powervault 122T on dedicated scsi card). I've turned off the antivirus, cpu load is typically around 15%, & it's not swapping.
What else can I look for that would impact my streaming performance with Arcserve 2K?
Hrm...only specs I can find on a 122T indicate that the data rate is 3MB/sec native and 6MB/sec compressed. Are you getting near 180MB/min or 360MB/min throughput? If you are, it's not too much to worry about.
If you aren't then I would look at the drive array. How many drives in your array? What are the manufacturer's specs? RAID-5 does add some overhead, but I would not expect that much. Also, lots of small files, smaller than the blocking size of the tape, can lead to frequent stops and starts.
If you have a seperate drivespace, one that is different than the one you are trying to back up, you can set up a test File System storage device and see what kind of throughput you are getting from the RAID subsystem.
Without knowing a little more about your setup, I can only guess as to the problem, sorry.
Regards,
Don Osicky
If you aren't then I would look at the drive array. How many drives in your array? What are the manufacturer's specs? RAID-5 does add some overhead, but I would not expect that much. Also, lots of small files, smaller than the blocking size of the tape, can lead to frequent stops and starts.
If you have a seperate drivespace, one that is different than the one you are trying to back up, you can set up a test File System storage device and see what kind of throughput you are getting from the RAID subsystem.
Without knowing a little more about your setup, I can only guess as to the problem, sorry.
Regards,
Don Osicky
- Thread starter
- #10
Thanks for your effort and explanations, IggyPop! This was a bit of an eye-opener for me. I know that the tape drive is not on the same bus as the RAID drives, but I will try out your other suggestions and hope for the best.
Once again, Thanks!
foland
Once again, Thanks!
foland
northstardave
MIS
I'm getting between 110 and 120 MB/m on average. Sometimes something will burst up to around 250 (i.e. a small registry backup or a small partition) but most sessions pull 110-120. However, my Novell server will average about 180 while my Linux servers (on the same lan as the Novell...) will do about 110 on a good day.
The RAID has 3 drives. It's the Dell PERC 3/Di controller but I don't know that much more about it. I am, however, checking into the possiblity that there are drivers that I need to update. I've got the latest controller drivers but I'm not sure about the "container" driver that shows up under Disk Drives in the hardware mgr.
As you suggest, I suspect that this may be related to the size of the files being less than the block size. I'm going to try switching to a smaller block size & see what happens.
thanks!!
The RAID has 3 drives. It's the Dell PERC 3/Di controller but I don't know that much more about it. I am, however, checking into the possiblity that there are drivers that I need to update. I've got the latest controller drivers but I'm not sure about the "container" driver that shows up under Disk Drives in the hardware mgr.
As you suggest, I suspect that this may be related to the size of the files being less than the block size. I'm going to try switching to a smaller block size & see what happens.
thanks!!
Hi Everyone,
I have just setup a new backup environment with the following specs.
<Backup Server>
DELL Poweredge 2650
2GB RAM
Dual CPU (2.0GHz)
Mirror C: (36GB)
Raid 5 D: (100GB)
Dell Powervault 132T LTO Library (2 Drives)
1000Base T NIC.
I am backing up approx 10 Server across a 100mb Switched LAN, with some servers connected via 100mb and some via 1000mb.
I am getting throughput of between 50mb/min to around 110mb/min.
This is not fast enough, to complete all my jobs within the allocated backup window.
How can I increase the throughput of my backups?
Any help is appreciated,
Ronnie
I have just setup a new backup environment with the following specs.
<Backup Server>
DELL Poweredge 2650
2GB RAM
Dual CPU (2.0GHz)
Mirror C: (36GB)
Raid 5 D: (100GB)
Dell Powervault 132T LTO Library (2 Drives)
1000Base T NIC.
I am backing up approx 10 Server across a 100mb Switched LAN, with some servers connected via 100mb and some via 1000mb.
I am getting throughput of between 50mb/min to around 110mb/min.
This is not fast enough, to complete all my jobs within the allocated backup window.
How can I increase the throughput of my backups?
Any help is appreciated,
Ronnie
NorthstarDave:
Don't know if you have the room to do this, or a group of files around that would suffice, but can you try and create/find a set of large files to backup? This should give you a better indication of performance without the filesystem overhead getting in the way.
Also, if your version of ARCServe supports it, create a FileSystem sotrage device and backup to that device. This should give you a good indication of the max speeds for the mechanisms involved. For instance, recently I setup a machine with the ARCServe 2000 Agent. This particular tape drive is rated at 600MB/sec. When I backup to tape I get about 410MB/min. When I backup to a FileSystem device, I still get about 410MB/min. This all makes sense. I am using 100BaseT to link the 2 machines, and the max limit on 100BaseT is 600MB/min. With protocol overhead, small files and other factors, I am pleased to squeeze out 350-400MB. To get anything better, I would have to provide additional pathways, more 100BaseT NICs, or replace the NIC with a gigabit solution. But since I am fairly close to the drive's mechanical limit it's going to stay where it is for now.
Another thing to note that tripped me up. Make sure you reformat old tapes with the different blocksize that you eventually settle on. I had something really weird going on a while back, and it was because my test tapes had different block sizes. Also check and make sure that the compression is enabled after you erase/format the tapes.
Ronnie001:
Yep, I would definitely expect better backup performance than that. I would point to the same things as I have said above. Create a FileSystem storage device and try backing up to it and see what you get.
I would assume that it is, but I have to ask. Is the tape library on its own SCSI Host Adapter?
Check the block size of the tape too. If it's anything less than 32K, I would push it up to at least that.
From your 100Base servers, expect a maximum of 600MB/min, with a more realistic range of 350/400MB/sec. From the 1000Base servers, although 10X the above numbers is the wire limit, the tape drives handle 900MB/min native - 1800MB/min compressed, which is the limiting factor.
Antivirus can be a badguy as well. If it's on, turn it off and run a test. You'll know whether it's causing problems or not.
I hope this helps in some way. It's all I can think of off the top of my head at the moment. Let us know how it all turns out....and good luck!
Regards,
Don Osicky
Don't know if you have the room to do this, or a group of files around that would suffice, but can you try and create/find a set of large files to backup? This should give you a better indication of performance without the filesystem overhead getting in the way.
Also, if your version of ARCServe supports it, create a FileSystem sotrage device and backup to that device. This should give you a good indication of the max speeds for the mechanisms involved. For instance, recently I setup a machine with the ARCServe 2000 Agent. This particular tape drive is rated at 600MB/sec. When I backup to tape I get about 410MB/min. When I backup to a FileSystem device, I still get about 410MB/min. This all makes sense. I am using 100BaseT to link the 2 machines, and the max limit on 100BaseT is 600MB/min. With protocol overhead, small files and other factors, I am pleased to squeeze out 350-400MB. To get anything better, I would have to provide additional pathways, more 100BaseT NICs, or replace the NIC with a gigabit solution. But since I am fairly close to the drive's mechanical limit it's going to stay where it is for now.
Another thing to note that tripped me up. Make sure you reformat old tapes with the different blocksize that you eventually settle on. I had something really weird going on a while back, and it was because my test tapes had different block sizes. Also check and make sure that the compression is enabled after you erase/format the tapes.
Ronnie001:
Yep, I would definitely expect better backup performance than that. I would point to the same things as I have said above. Create a FileSystem storage device and try backing up to it and see what you get.
I would assume that it is, but I have to ask. Is the tape library on its own SCSI Host Adapter?
Check the block size of the tape too. If it's anything less than 32K, I would push it up to at least that.
From your 100Base servers, expect a maximum of 600MB/min, with a more realistic range of 350/400MB/sec. From the 1000Base servers, although 10X the above numbers is the wire limit, the tape drives handle 900MB/min native - 1800MB/min compressed, which is the limiting factor.
Antivirus can be a badguy as well. If it's on, turn it off and run a test. You'll know whether it's causing problems or not.
I hope this helps in some way. It's all I can think of off the top of my head at the moment. Let us know how it all turns out....and good luck!
Regards,
Don Osicky
Hi Don,
Thanks for the information.
I created a FileSystem storage device and did 2 backups to that:
One of the backup server itself (locally) - 545mb/min
One of a remote machine running the W2K agent, over a 100mb LAN - 433mb/min.
My tape library is on its own SCSI adapter.
My tape block size is 65536.
Any ideas?
Regards,
Ronnie
Thanks for the information.
I created a FileSystem storage device and did 2 backups to that:
One of the backup server itself (locally) - 545mb/min
One of a remote machine running the W2K agent, over a 100mb LAN - 433mb/min.
My tape library is on its own SCSI adapter.
My tape block size is 65536.
Any ideas?
Regards,
Ronnie
Greetings Ronnie,
The FileSystem storage device numbers look great! You have eliminated the servers, RAID subsystems and LAN as potential sources of the problem. Now we can focus on the tape subsystem.
First, check and make sure you have the current SCSI Host Adapter drivers loaded. Also make sure that you have the correct settings in BIOS for your device.
Termination can be an issue sometimes as well. Check and make sure that the terminator hasn't been dislodged.
On the ARCServe side, make sure that you have the current tape device driver service pack. Don't think I caught which version of ARCServe you are on, but I am thinking it's 2000. If this is the case, make sure you have service pack 4 + the driver update done. Also make sure to apply service pack 4 to the Agent servers as well.
Last thing that I can think to try is changing the block size and making it a little smaller. And before anyone flames me, it's only something to try folks. I have seen the "illogical" work all to often in this world. Try a block size of 32K then 16K and see if your results decrease or increase.
I will think on this some more, but that is what I come up with as of now. Maybe after the coffee has kicked in I will come up with more.
Regards,
Don Osicky
The FileSystem storage device numbers look great! You have eliminated the servers, RAID subsystems and LAN as potential sources of the problem. Now we can focus on the tape subsystem.
First, check and make sure you have the current SCSI Host Adapter drivers loaded. Also make sure that you have the correct settings in BIOS for your device.
Termination can be an issue sometimes as well. Check and make sure that the terminator hasn't been dislodged.
On the ARCServe side, make sure that you have the current tape device driver service pack. Don't think I caught which version of ARCServe you are on, but I am thinking it's 2000. If this is the case, make sure you have service pack 4 + the driver update done. Also make sure to apply service pack 4 to the Agent servers as well.
Last thing that I can think to try is changing the block size and making it a little smaller. And before anyone flames me, it's only something to try folks. I have seen the "illogical" work all to often in this world. Try a block size of 32K then 16K and see if your results decrease or increase.
I will think on this some more, but that is what I come up with as of now. Maybe after the coffee has kicked in I will come up with more.
Regards,
Don Osicky
northstardave
MIS
Just as a followup...
I did the filesystem test & my numbers did not change significantly.
I'll dive back into it one day when I've got time to really tear it apart & find the bottleneck.
Until then...
I did the filesystem test & my numbers did not change significantly.
I'll dive back into it one day when I've got time to really tear it apart & find the bottleneck.
Until then...
Hi Don,
Thanks for the advice.
I have checked and upgraded my SCSI drivers for my LTO Library and this has improved things significantly.
I have also put my backup server onto a gigabit connection and also my mail server onto a gigabit connection. This means that backup of exchange is giving me throughputs of an average 1,300mb/min.
Most other servers are giving throughput of 300-400mb/min which is good. (these servers are running on 100mb LAN)
But 4 of my Citrix servers are only getting 40-50mb/min which I am now trying to resolve. Thinking of updating the NIC drivers on these systems....
FYI, I am running Brightstor Arcserve version 9.
Regards,
Ronnie
Thanks for the advice.
I have checked and upgraded my SCSI drivers for my LTO Library and this has improved things significantly.
I have also put my backup server onto a gigabit connection and also my mail server onto a gigabit connection. This means that backup of exchange is giving me throughputs of an average 1,300mb/min.
Most other servers are giving throughput of 300-400mb/min which is good. (these servers are running on 100mb LAN)
But 4 of my Citrix servers are only getting 40-50mb/min which I am now trying to resolve. Thinking of updating the NIC drivers on these systems....
FYI, I am running Brightstor Arcserve version 9.
Regards,
Ronnie
TomMartino
Technical User
Hi Don
How do you check the Block size in 2000 AE ?
Thanks
Tom
How do you check the Block size in 2000 AE ?
Thanks
Tom
northstardave
MIS
Another update on my progress:
I did some tweaking of the internal buffer sizes (increased the Default 384K buffer) & now my filesystem backups are running between 500-600MB/min which is fantastic!! The downside is that my tape backups are running as slowly as ever. As we speak I'm getting 109.60 MB/min. Double-plus-un-good.
All my tapes show a block size of 65536. Any suggestions?
Thanks
I did some tweaking of the internal buffer sizes (increased the Default 384K buffer) & now my filesystem backups are running between 500-600MB/min which is fantastic!! The downside is that my tape backups are running as slowly as ever. As we speak I'm getting 109.60 MB/min. Double-plus-un-good.
All my tapes show a block size of 65536. Any suggestions?
Thanks
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