I have 8 WD SATA HDD with raid ready (3mbps) hard disks on a 8 port 3ware controller.(on raid 5.) Does anyone have a comparison on SATA raid and SAS raid disk. As you know SAS disk are very expensive and I would like to know from experts in the list who could suggest which of the following would be the best.
Option 1) 2 servers each having 2.0TB raid disk with SAS drives, 2GB ram and standard other features.
Option 2) 4 No servers with 1TB each with 2GB ram and standard other features.
If Data files (mostly AutoCAD Drawings of size 5MB to 50MB) are distributed as per the above options do you think which could perform better?. As you know the price of SATA disk is much cheaper than the SAS disk and we could nearly by 4 servers for that money.
Probability work disturbed by a server crash is low in the second case but I am not sure about the comparison on performance.
I would appreciate if you could spread some thought in this regards, and apologize if this is out of topic.
Best regards,
Rajeev
On Wednesday 22 August 2007, Rajeev R Veedu wrote:
I have 8 WD SATA HDD with raid ready (3mbps) hard disks on a 8 port 3ware controller.(on raid 5.) Does anyone have a comparison on SATA raid and SAS raid disk. As you know SAS disk are very expensive and I would like to know from experts in the list who could suggest which of the following would be the best.
I got a 4 port 9650 with 4 750GB Seagate drives in raid 0+1 on it for data storage, and a 8port LSI LSI00110 with 4 36GB 15K rpm disks, again raid 0+1, for the OS and swap. When I take a ext3 filesystem and run bonnie++ then the SATA solution is about 60% faster for sequential reads. However, for random access, the SAS solution is about 3 times faster.
So - as always in this world - the answer depends on your usage pattern.
Option 1) 2 servers each having 2.0TB raid disk with SAS drives, 2GB ram and standard other features.
Option 2) 4 No servers with 1TB each with 2GB ram and standard other features.
If Data files (mostly AutoCAD Drawings of size 5MB to 50MB) are distributed as per the above options do you think which could perform better?. As you know the price of SATA disk is much cheaper than the SAS disk and we could nearly by 4 servers for that money.
Its been a while since I did AutoCAD but anyway - why only 2GB? As for the IO, AutoCAD (assuming you have enough ram so your system doesn't swap) doesn't do a lot of i/o - and if so, its mostly sequential. So, without having tried it, my guess is that you will not see much of a difference either way. I'd go with the 4 servers.
On the other hand, data reliability is another issue. We have tons of sata based disk arrays and have had no issues yet (because our systems are all on UPS and multiple circuits) but if you don't have infrastructure like that, you are more likely to lose data on a sata based system...
I personally would still go sata.
Peter.
-----Original Message----- From: centos-bounces@centos.org [mailto:centos-bounces@centos.org] On Behalf Of Rajeev R Veedu Sent: Wednesday, August 22, 2007 2:52 AM To: 'CentOS mailing list' Subject: [CentOS] SATA vs. SAS
I have 8 WD SATA HDD with raid ready (3mbps) hard disks on a 8 port 3ware controller.(on raid 5.) Does anyone have a comparison on SATA raid and SAS raid disk. As you know SAS disk are very expensive and I would like to know from experts in the list who could suggest which of the following would be the best.
As a lot of people have probably said the answer depends on your workload.
If the workload is mostly small random io I would go with 15K SAS configured into a raid10.
If the workload is mostly fairly large sequential reads/writes (file server) then I would probably go with SATA 7200 RAID5/6 or RAID50/60.
If doing databases set the chunk size to the maximum size of a data dump i/o (usually 1MB) so each dump i/o hits a separate spindle, for random it doesn't really matter cause it's random, you just want the fastest access time money can afford.
For file services you will have to gauge the chunk size by the type of files, mostly small, small chunks, mostly large, then larger chunks, 64K is the standard middle-of the road here.
Option 1) 2 servers each having 2.0TB raid disk with SAS drives, 2GB ram and standard other features.
If going down this road, why not look into getting one of those fancy new storage enclosures where the RAID is built into the enclosure and can allow 2 servers to simultaneously access the arrays with full battery backed write-back cache?
Option 2) 4 No servers with 1TB each with 2GB ram and standard other features.
I don't know if I follow you here...
If Data files (mostly AutoCAD Drawings of size 5MB to 50MB) are distributed as per the above options do you think which could perform better?. As you know the price of SATA disk is much cheaper than the SAS disk and we could nearly by 4 servers for that money.
If that's the workload, then save the money and go SATA in a RAID50 (two RAID5's striped), say a 4-spindle/4-spindle if you could go to say 10-12 disks then do a 5-spindle/5-spindle with 1 or 2 hotspares.
Probability work disturbed by a server crash is low in the second case but I am not sure about the comparison on performance.
Look at a shared storage solution so you can have the storage fail-over in the even of a server crash rather then replicate it.
I would appreciate if you could spread some thought in this regards, and apologize if this is out of topic.
Best regards,
Rajeev
______________________________________________________________________ This e-mail, and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail, you are hereby notified that any dissemination, distribution or copying of this e-mail, and any attachments thereto, is strictly prohibited. If you have received this e-mail in error, please immediately notify the sender and permanently delete the original and any copy or printout thereof.
Option 1) 2 servers each having 2.0TB raid disk with SAS drives, 2GB ram and standard other features.
If going down this road, why not look into getting one of those fancy new storage enclosures where the RAID is built into the enclosure and can allow 2 servers to simultaneously access the arrays with full battery backed write-back cache?
What is available for Linux in this department?
-----Original Message----- From: centos-bounces@centos.org [mailto:centos-bounces@centos.org] On Behalf Of Feizhou Sent: Wednesday, August 22, 2007 9:54 AM To: CentOS mailing list Subject: Re: [CentOS] SATA vs. SAS
Option 1) 2 servers each having 2.0TB raid disk with SAS drives, 2GB ram and standard other features.
If going down this road, why not look into getting one of those fancy new storage enclosures where the RAID is built into the enclosure and can allow 2 servers to simultaneously access the arrays with full battery backed write-back cache?
What is available for Linux in this department?
I'm testing out an MD3000 from Dell. It can allow 4 hosts with single 4x serial paths, or 2 hosts with redundant 4x serial and can chain up to 2 MD1000s off it for up to 45 spindles.
It was 2 RAID controllers in 2 EMMs with 512MB BBU write-back that is synchronized between them which act as redundant RAID controllers. Ships with 4 plain-jane 2 path SAS controllers for host systems.
Downside, right now, it currently only supports SAS drives, they hope to have a SAS/SATA firmware update maybe by year-end.
-Ross
______________________________________________________________________ This e-mail, and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail, you are hereby notified that any dissemination, distribution or copying of this e-mail, and any attachments thereto, is strictly prohibited. If you have received this e-mail in error, please immediately notify the sender and permanently delete the original and any copy or printout thereof.
Option 1) 2 servers each having 2.0TB raid disk with SAS drives, 2GB ram and standard other features.
If going down this road, why not look into getting one of those fancy new storage enclosures where the RAID is built into the enclosure and can allow 2 servers to simultaneously access the arrays with full battery backed write-back cache?
What is available for Linux in this department?
I'm testing out an MD3000 from Dell. It can allow 4 hosts with single 4x serial paths, or 2 hosts with redundant 4x serial and can chain up to 2 MD1000s off it for up to 45 spindles.
It was 2 RAID controllers in 2 EMMs with 512MB BBU write-back that is synchronized between them which act as redundant RAID controllers. Ships with 4 plain-jane 2 path SAS controllers for host systems.
Downside, right now, it currently only supports SAS drives, they hope to have a SAS/SATA firmware update maybe by year-end.
Binary drivers from Dell?
-----Original Message----- From: centos-bounces@centos.org [mailto:centos-bounces@centos.org] On Behalf Of Feizhou Sent: Wednesday, August 22, 2007 10:54 AM To: CentOS mailing list Subject: Re: [CentOS] SATA vs. SAS
Option 1) 2 servers each having 2.0TB raid disk with SAS drives, 2GB ram and standard other features.
If going down this road, why not look into getting one of those fancy new storage enclosures where the RAID is built into the enclosure and can allow 2 servers to simultaneously access the arrays with full battery backed write-back cache?
What is available for Linux in this department?
I'm testing out an MD3000 from Dell. It can allow 4 hosts with single 4x serial paths, or 2 hosts with redundant 4x serial and can chain up to 2 MD1000s off it for up to 45 spindles.
It was 2 RAID controllers in 2 EMMs with 512MB BBU write-back that is synchronized between them which act as redundant RAID controllers. Ships with 4 plain-jane 2 path SAS controllers for host systems.
Downside, right now, it currently only supports SAS drives, they hope to have a SAS/SATA firmware update maybe by year-end.
Binary drivers from Dell?
The HBA that connects to the MD3000 is just an mptsas driver which is part of the stock kernel, but you can download the latest version from Dell's website as a dkms source package.
-Ross
______________________________________________________________________ This e-mail, and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail, you are hereby notified that any dissemination, distribution or copying of this e-mail, and any attachments thereto, is strictly prohibited. If you have received this e-mail in error, please immediately notify the sender and permanently delete the original and any copy or printout thereof.
On Wednesday 22 August 2007, Rajeev R Veedu wrote: ...
Option 1) 2 servers each having 2.0TB raid disk with SAS drives, 2GB ram and standard other features.
Option 2) 4 No servers with 1TB each with 2GB ram and standard other features.
Late comment on this thread. Really short comment actually:
SAS vs. SATA is not the issue, raid controller A vs. B is.
/Peter
-
Feizhou -
Peter Arremann -
Peter Kjellstrom -
Rajeev R Veedu -
Ross S. W. Walker