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Originally Posted by Shadow_UGZ  Nice. Remember though enabling write back cache increases chances of data loss since some data is temporarily cached in the CPU L1 cache. So during a power loss or forced shutdown of any kind you can corrupt files. I also don't think it helps that you have a RAID0 with that enabled. Other than that, that's a pretty nice increase in speed
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| Write back caches are implemented on hard disks to enhance write performance. ATA drives, in particular, rely on write back caches to make up for the slower performance due to slower seek-time and RPM when compared to their SCSI / Fibre Channel counterparts. Some RAID controllers further implement write cache on the controllers to enhance the overall performance of the system. With write back caching turned on by default, an ATA drive can signal the completion of writes more quickly than if it had to wait until the data was completely transferred to the disk media. However, in the even of a failure (such as power failure, hardware failure, etc.), data corruption may happen if the data on the disk cache has not been flushed out to the disk media. Another problem with ATA write back cache is that data may be flushed out to disks out-of-order, i.e., if block A arrives to cache before block B, block B may be flushed out to disk before block A. While turning the write back cache off for ATA disks will avoid data corruption problem, performance will degrade. In addition, the drives will be used in a less reliable mode, since ATA vendors do not certify the recovery of drives that deactivate write-back caching. The chance of data corruption increases with RAID system that leaves write back cache on. A RAID system write stripes that span multiple disks. Since there is no guarantee that all data blocks in a stripe will be flushed out to disk media, the stripe may not be consistent. In the ATA world, hardware RAID vendors typically leave disk write back cache on by default. Some provide options to turn write back cache off --- for example, the user manual for 3ware RAID controller warns users that "there may be instances when you always want the computer to wait for the drive to write all the data to disk before going to its next task ... you must disable the write cache." (page 54-55 of 3ware RAID controller user manual). |
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Originally Posted by AMD+nVidia Huh? |
Originally Posted by ericeod Check out the performance differene with a RAID setup with Write-back cache disabled, then enabled. Grunion's screenshots show CC Cleaner being completed at different times with it disabled and enabled... |
Originally Posted by AMD+nVidia It says 0 removed though... |
Originally Posted by ericeod But it still ran a scan. Look at the time for competion. |
Originally Posted by AMD+nVidia So it scanned faster for nothing? Sorry, just seems pointless to me, can you post a SS with it removing stuff? |
Originally Posted by Shadow_UGZ Nice. Remember though enabling write back cache increases chances of data loss since some data is temporarily cached in the CPU L1 cache. So during a power loss or forced shutdown of any kind you can corrupt files. I also don't think it helps that you have a RAID0 with that enabled. |
Originally Posted by the_beast Write-back caching has nothing to do with the cpu cache. That is used exclusively by the cpu. The ICH10R uses a portion of system memory for its cache. This is what the OP activated, and it can make a huge difference to performance. True hardware RAID controllers also often have an onboard cache which can be enabled or disabled, and which is often protected by a battery to prevent problems. Unless you are running a RAID5 or 6 array, which might hold data in the cache for some time before being written there is little extra risk of data loss when using write-back over what you normally get - HDDs have onboard cache that is enabled by default, and if disabled performance goes down the toilet. There is really no valid reason to run onboard RAID0 and not use write-back - if data integrity is your aim, then you should stick with a more reliable storage method than RAID0 anyway, or at least get a hardware card with cache & BBU and switch off the disk cache. |
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Originally Posted by the_beast Write-back caching has nothing to do with the cpu cache. That is used exclusively by the cpu. The ICH10R uses a portion of system memory for its cache. This is what the OP activated, and it can make a huge difference to performance. True hardware RAID controllers also often have an onboard cache which can be enabled or disabled, and which is often protected by a battery to prevent problems. Unless you are running a RAID5 or 6 array, which might hold data in the cache for some time before being written there is little extra risk of data loss when using write-back over what you normally get - HDDs have onboard cache that is enabled by default, and if disabled performance goes down the toilet. There is really no valid reason to run onboard RAID0 and not use write-back - if data integrity is your aim, then you should stick with a more reliable storage method than RAID0 anyway, or at least get a hardware card with cache & BBU and switch off the disk cache. |
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Originally Posted by the_beast Write-back caching has nothing to do with the cpu cache. That is used exclusively by the cpu. The ICH10R uses a portion of system memory for its cache. This is what the OP activated, and it can make a huge difference to performance. True hardware RAID controllers also often have an onboard cache which can be enabled or disabled, and which is often protected by a battery to prevent problems. Unless you are running a RAID5 or 6 array, which might hold data in the cache for some time before being written there is little extra risk of data loss when using write-back over what you normally get - HDDs have onboard cache that is enabled by default, and if disabled performance goes down the toilet. There is really no valid reason to run onboard RAID0 and not use write-back - if data integrity is your aim, then you should stick with a more reliable storage method than RAID0 anyway, or at least get a hardware card with cache & BBU and switch off the disk cache. |
Originally Posted by AMD+nVidia So how do I enable this? I brought that thing up and can't enable it |
Originally Posted by ericeod Right click on the drive or array, then click on "enable write-back cache. For example, on grunion's ss you would right click on "Rapts" listed just below "Volumes". |
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Originally Posted by ericeod Intel and NVIDIA onboard RAID controllers disable write-back cache by default. You can corrupt your OS while BSODing and crashing when write-back cache is enabled. |
