We currently have a Quantum/ATL library with built in NDMP tape drives (SDLT220) and are moving to a StorageTek library with Dinostor (http://www.dinostor.com) NDMP bridges and LTO1 drives.
We use a separate gigabit network for backups, and see 20MB/s to the SDLT drives. A FAS960 can push 5-6 streams at 20MB/s. Even with a single stream, I haven't seen much above 20MB/s, so the drive seems to be the limiting factor in this case. Our old F760 used to be able to do 3 streams at 20MB/s, but would drop to 12-15MB/s if pushed to 4 streams.
Dropping in a Dinostor in place of your tape host filer would take the load off that filer. What rates are you seeing?
John
-----Original Message----- From: Geoff Hardin [mailto:geoff.hardin@dalsemi.com] Sent: Tuesday, November 02, 2004 3:24 PM To: toasters Subject: Backup speeds across the network
We have several filers and few tape drives so we are looking at doing 3-way NDMP backups. Right now, we are doing those backups to other filers, but this is consuming a lot of resources, especially on the tape host filer. So, we are looking at a new tape library from SpectraLogic, Overland, Quantum, StorageTek, etc. that has the NDMP "built-in" to the tape drive.
Our question is, what kind of speeds are others seeing in their real environments? Speaking to one vendor, they claimed their library would work at the rated tape speeds (35 MB/s), while another claimed even better performance (40 MB/s); to his credit, the second vendor said that he wasn't the technical guy, but he thought that's what he remembered. Call me overly cynical, but I find it hard to believe that we will see speeds comparable to direct attached tape over the network. Our experience in the past has been somewhere closer to 50% of the rated tape speed, and even that may be a bit overreaching for some of our older filers (F760C).
Thanks,
Geoff Hardin geoff.hardin@dalsemi.com UNIX System Administrator Maxim / Dallas Semiconductor
Currently we are seeing about 4.5 MB/s from the filer (F760) to an LTO-2 drive attached to a Sun V240. Unfortunately, we do not have any data on the FAS270 yet, so we can't really test it, which is why I was looking for other's results.
We looked at the DinoStor tape hosts and have been interested in using them for years, but we couldn't justify the additional price when there are libraries that have the functionality built-in already. From our own evaluations though, we highly recommend using the DinoStor devices if your library can not be attached to the network.
Geoff Hardin UNIX System Administrator / Team Lead Dallas Semiconductor / Maxim Integrated Products 972-371-4630 geoff.hardin@dalsemi.com Famous last words: Who? Me?
On Tue, 2 Nov 2004, John Clear wrote:
We currently have a Quantum/ATL library with built in NDMP tape drives (SDLT220) and are moving to a StorageTek library with Dinostor (http://www.dinostor.com) NDMP bridges and LTO1 drives.
We use a separate gigabit network for backups, and see 20MB/s to the SDLT drives. A FAS960 can push 5-6 streams at 20MB/s. Even with a single stream, I haven't seen much above 20MB/s, so the drive seems to be the limiting factor in this case. Our old F760 used to be able to do 3 streams at 20MB/s, but would drop to 12-15MB/s if pushed to 4 streams.
Dropping in a Dinostor in place of your tape host filer would take the load off that filer. What rates are you seeing?
John
-----Original Message----- From: Geoff Hardin [mailto:geoff.hardin@dalsemi.com] Sent: Tuesday, November 02, 2004 3:24 PM To: toasters Subject: Backup speeds across the network
We have several filers and few tape drives so we are looking at doing 3-way NDMP backups. Right now, we are doing those backups to other filers, but this is consuming a lot of resources, especially on the tape host filer. So, we are looking at a new tape library from SpectraLogic, Overland, Quantum, StorageTek, etc. that has the NDMP "built-in" to the tape drive.
Our question is, what kind of speeds are others seeing in their real environments? Speaking to one vendor, they claimed their library would work at the rated tape speeds (35 MB/s), while another claimed even better performance (40 MB/s); to his credit, the second vendor said that he wasn't the technical guy, but he thought that's what he remembered. Call me overly cynical, but I find it hard to believe that we will see speeds comparable to direct attached tape over the network. Our experience in the past has been somewhere closer to 50% of the rated tape speed, and even that may be a bit overreaching for some of our older filers (F760C).
Thanks,
Geoff Hardin geoff.hardin@dalsemi.com UNIX System Administrator Maxim / Dallas Semiconductor
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Geoff Hardin -
John Clear