December 29, 2014 at 6:15 am
I was taking full backup everyday on a E:\ drive and it was taking more than 2 hours. Because of space issue I started taking backup on J:\ and it is only taking 45 min. for the same full backup.
My question is how can I prove the E:\ was slower or J:\ is faster. Is there anyway I can prove this showing write matrix? Another word where I can see 'write' on LUN when taking full backup or after taking backup?
December 29, 2014 at 2:12 pm
If you aren't doing a backup to a local disk, then it's either another server across the network, or it's a SAN, across a SAN network. Either way, you're looking at either lack of overall network bandwidth for the network being traversed, or contention of use of the available bandwidth. What, exactly, are the technologies behind the E:\ drive and the J:\ drive? Are both of them SANs ? What speed is the SAN network? Remember that a typical local hard drive can run full blast at 5 to 6 gigabits per second, if you can feed it enough data. The fastest of the fiber SAN networks that I know about are 10 Gigabits per second, but most of them are just 1 Gigabit per second, so the speed matters a LOT. If you want to look at Perfmon counters, take a look at I/O Wait and compare it for both drives.
Steve (aka sgmunson) 🙂 🙂 🙂
Rent Servers for Income (picks and shovels strategy)
December 30, 2014 at 7:09 am
First, thanks for your reply. It was moved from DAS to Local Drive. Now it's faster.
December 30, 2014 at 7:21 am
You didn't mention what technology "DAS" is, but I have to assume that since local disk is faster, that it's probably a SAN. Are you good to go at this point, or do you have more questions?
Steve (aka sgmunson) 🙂 🙂 🙂
Rent Servers for Income (picks and shovels strategy)
December 30, 2014 at 2:45 pm
sgmunson (12/30/2014)
You didn't mention what technology "DAS" is, but I have to assume that since local disk is faster, that it's probably a SAN. Are you good to go at this point, or do you have more questions?
DAS would not be a SAN, afai understand it, they're mutually exclusive.
SQL DBA,SQL Server MVP(07, 08, 09) A socialist is someone who will give you the shirt off *someone else's* back.
December 30, 2014 at 9:39 pm
Okay Scott... what, exactly, is "DAS" ? I'm usually in a contract role, and usually for long enough that I don't stay in one place for all that long, or if I do, I end up somewhat isolated, so there's a lot that goes on that I don't hear about, and I haven't had the chance to read up much on the latest disk technologies.
Steve (aka sgmunson) 🙂 🙂 🙂
Rent Servers for Income (picks and shovels strategy)
December 31, 2014 at 8:51 am
sgmunson (12/30/2014)
Okay Scott... what, exactly, is "DAS" ? I'm usually in a contract role, and usually for long enough that I don't stay in one place for all that long, or if I do, I end up somewhat isolated, so there's a lot that goes on that I don't hear about, and I haven't had the chance to read up much on the latest disk technologies.
"direct attached storage", or directly attached to the server itself!
December 31, 2014 at 9:17 am
Thanks fpr the info. Interesting that someone coined the term "DAS", because while SATA or e-SATA would qualify under that umbrella, so would a USB attached drive, as the connection is direct, but the device itself is usually of the portable variety, and it seems to me that calling a portable device DAS doesn't quite make sense... Oh well...
Steve (aka sgmunson) 🙂 🙂 🙂
Rent Servers for Income (picks and shovels strategy)
December 31, 2014 at 9:54 am
I think DAS was coined when expansion boxes attached to servers using external SCSI connections. This distinguishes it from storage across a network using HBAs, SAN, iSCSI, etc.
You are correct that usb drives, etc are DAS
December 31, 2014 at 10:17 am
Steve Jones - SSC Editor (12/31/2014)
I think DAS was coined when expansion boxes attached to servers using external SCSI connections. This distinguishes it from storage across a network using HBAs, SAN, iSCSI, etc.You are correct that usb drives, etc are DAS
Quick thought/assumption, guess it's more like Dell's PowerVault, HP's Enterprise Disk Enclosures and such, normally a much fatter pipe than USB;-) Rather refer to the USB drives as External HD.
😎
December 31, 2014 at 11:53 am
sgmunson (12/31/2014)
Thanks fpr the info. Interesting that someone coined the term "DAS", because while SATA or e-SATA would qualify under that umbrella, so would a USB attached drive, as the connection is direct, but the device itself is usually of the portable variety, and it seems to me that calling a portable device DAS doesn't quite make sense... Oh well...
Wikipedia calls it a 'retronym', which is a pretty nifty term IMO! I like the retronym take on it because before SAN technology, folks probably didn't even see the need to mention how storage was connected. Maybe DAS can be used for any storage that doesn't connect via a network, but then we'll have to start talking about what a network is versus a connection bus.
December 31, 2014 at 12:06 pm
Yeah, don't EVEN get me started down THAT road... 'Tis a slippery road, and many a folk out there who see the road as half ice instead of half clear... And what we're talkin' about here is makin' both sides of the road covered with slippery stuff... :-P:-P:-P
Steve (aka sgmunson) 🙂 🙂 🙂
Rent Servers for Income (picks and shovels strategy)
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