My guess is that they are not measuring those parameters (Latency). Regarding Health rating, I believe that has to do with the number of starts and hours of service. More important to me are the read/write/seek/sector errors. On a few month old Seagate Barracuda drives, these numbers are large, so I don’t know at what point those numbers become too big and I have to replace the drive.
Regards, John > On Dec 1, 2015, at 5:31 AM, mickeyf <[email protected]> wrote: > > My ignorance of this stuff is very nearly 100%, but why does "Issues found : > 0" equate to 'Only' "Overall Health Rating 89.9%" ? > > Also, how do they get : > "Latency Time (Read) : 0 ns" > "Latency Time (Write) : 0 ns" > > ...unless this was programmed by the "rogue engineers" at Volkswagon? Surely > it has latency > 0? > > Real questions, not facetious, just curious. > > > On Sunday, November 29, 2015 at 2:32:22 PM UTC-8, john3909 wrote: > Hi William, > > My comment was just a heads up so other developer’s don’t get take a hit like > I did. Just look at your disk SMART data and you will be surprised by the > number of errors on those disks. Here is an example of SMART info from one of > my 4TB WD disks I use with TimeMachine. As you can see, 0 errors in the log. > On my development system, I use 1TB Seagate SSD drives and they work great. > > Last Checked : November 29, 2015 2:25:14 PM PST > Last Checked (ISO 8601 format) : 2015-11-29T14:25:14 > > Advanced SMART Status : OK > Overall Health Rating : GOOD 89.9% > Overall Performance Rating : GOOD 89.9% > Issues found : 0 > > Serial Number : WD-WCC4E0HHFLY1 > WWN Id : 5 0014ee 260fbf0bd > Volumes : TimeMachine1 > Device Path : /dev/disk4 > Total Capacity : 4.0 TB (4,000,787,030,016 Bytes) > Model Family : Western Digital Red > Model : WDC WD40EFRX-68WT0N0 > Firmware Version : 82.00A82 > Drive Type : HDD 5400 rpm > > Power On Time : 5,078 hours (7 months 1 days 14 hours) > Power Cycles Count : 54 > Current Power Cycle Time : 22.1 hours > > > > === DEVICE CAPABILITIES === > S.M.A.R.T. support enabled : yes > DriveDx Active Diagnostic Config : Base config [hdd.default] > Sector Logical Size : 512 > Sector Physical Size : 4096 > Physical Interconnect : SATA > Removable : no > Ejectable : no > ATA Version : ACS-2 (minor revision not indicated) > SATA Version : SATA 3.0, 6.0 Gb/s (current: 6.0 Gb/s) > Bay # : 1 > I/O Path : > IOService:/AppleACPIPlatformExpert/PCI0@0/AppleACPIPCI/PEG1@1,1/IOPP/UPSB@0/IOPP/DSB2@4/IOPP/UPS0@0/IOPP/pci-bridge@3/IOPP/pci1b21,612@0/AppleAHCI/PRT0@0/IOAHCIDevice@0/AppleAHCIDiskDriver/IOAHCIBlockStorageDevice > Attributes Data Structure Revision : 16 > SMART Command Transport (SCT) flags : 0x703d > SCT Status supported : yes > SCT Feature Control supported : yes > SCT Data Table supported : yes > Error logging capabilities : 0x1 > Self-tests supported : yes > Offline Data Collection capabilities : 0x7b > Offline Data Collection status : 0x0 > Auto Offline Data Collection flags : 0x0 > [Known device ]: yes > [Drive State Flags ]: 0x0 > > > === CURRENT POWER CYCLE STATISTICS === > Data Read : 2.2 GB > Data Written : 3.5 GB > Data Read/Write Ratio : 0.62 > Average Throughput (Read) : 1.2 MB/s > Average Throughput (Write) : 932.4 KB/s > > Operations (Read) : 175,372 > Operations (Write) : 153,554 > Operations Read/Write Ratio : 1 > Throughput per operation (Read) : 12.9 KB/Op > Throughput per operation (Write) : 23.6 KB/Op > > Latency Time (Read) : 0 ns > Latency Time (Write) : 0 ns > Retries (Read) : 0 > Retries (Write) : 0 > Errors (Read) : 0 > Errors (Write) : 0 > > > === PROBLEMS SUMMARY === > Failed Indicators (life-span / pre-fail) : 0 (0 / 0) > Failing Indicators (life-span / pre-fail) : 0 (0 / 0) > Warnings (life-span / pre-fail) : 0 (0 / 0) > Recently failed Self-tests (Short / Full) : 0 (0 / 0) > I/O Errors Count : 0 (0 / 0) > Time in Under temperature : 0 minutes > Time in Over temperature : 0 minutes > > > === IMPORTANT HEALTH INDICATORS === > ID NAME RAW VALUE > STATUS > 5 Reallocated Sector Count 0 > 100% OK > 197 Current Pending Sectors Count 0 > 100% OK > 198 Offline Uncorrectable Sector Count 0 > 100% OK > 199 UDMA CRC Error Count 0 > 100% OK > > > === TEMPERATURE INFORMATION (CELSIUS) === > Current Temperature : 33 > Power Cycle Min Temperature : 27 > Power Cycle Max Temperature : 37 > Lifetime Min Temperature : 23 > Lifetime Max Temperature : 49 > Recommended Min Temperature : 0 > Recommended Max Temperature : 60 > Temperature Min Limit : -41 > Temperature Max Limit : 85 > > > === DRIVE HEALTH INDICATORS === > ID | NAME | TYPE | UPDATE | RAW > VALUE | VALUE | THRESHOLD | WORST | STATUS | LAST > MODIFIED > 1 Raw Read Error Rate Pre-fail online > 0x0 200 51 200 100% OK > 5/13/15 8:43 PM > 3 Spin Up Time Pre-fail online > 7,891 182 21 177 89.9% OK > 11/29/15 2:25 PM > 4 Start Stop Count Life-span online > 4,129 96 0 96 96.0% OK > 11/29/15 2:25 PM > 5 Reallocated Sector Count Pre-fail online > 0 200 140 200 100% OK - > > 7 Seek Error Rate Life-span online > 0x0 200 0 200 100% OK - > > 9 Power On Hours Life-span online > 5,078 94 0 94 94.0% OK > 11/29/15 2:25 PM > 10 Spin Retry Count Life-span online > 0 100 0 100 100% OK - > > 11 Calibration Retry Count Life-span online > 0 100 0 253 100% OK - > > 12 Power Cycle Count Life-span online > 54 100 0 100 100% OK > 11/28/15 4:19 PM > 192 Power-Off Retract Count Life-span online > 21 200 0 200 100% OK > 11/12/15 2:02 PM > 193 Load Cycle Count Life-span online > 9,125 197 0 197 98.5% OK > 11/29/15 2:25 PM > 194 Temperature (Celsius) Life-span online > 33 119 0 103 99.2% OK > 11/29/15 2:25 PM > 196 Reallocated Event Count Life-span online > 0 200 0 200 100% OK - > > 197 Current Pending Sectors Count Life-span online > 0 200 0 200 100% OK - > > 198 Offline Uncorrectable Sector Count Life-span offline > 0 100 0 253 100% OK - > > 199 UDMA CRC Error Count Life-span online > 0 200 0 200 100% OK - > > 200 Multi Zone Error Rate Life-span offline > 0 100 0 253 100% OK - > > > > > === DRIVE ERROR LOG === > error log is empty > > > === DRIVE SELF-TEST LOG === > self-test log is empty > > > Regards, > John > > > > >> On Nov 29, 2015, at 1:42 PM, William Hermans <yyr...@ <>gmail.com >> <http://gmail.com/>> wrote: >> >> . . .the only purpose of a RAID backup is to prevent a single point of >> failure (like a disk failure) resulting in lost backups. >> >> You do not need a RAID array to prevent a single point of failure. You take >> those 3+ disks, put them in 3 different machines. Or even in the same >> machine as single drives. Same difference, only less wear and tear on the >> drives, more cost effective, and perhaps a small amount slower as singles. >> >> In the field you'll likely not run into any RAID 5/6 arrays. At least for >> corporate storage. You're more likely to see RAID10, or RAID0 + 1. Because >> there is nothing faster than striping disks, and RAID1 does not have an >> impact on performance if set up correctly. RAID5/6 is just a way for the >> home user to feel all warm and fuzzy . . and literally feed the companies >> who offer the hardware for such arrays. Be it controllers, or "special" hard >> drives . . . special software, chipsets with BS built in RAID( software ). >> >> I still use Seagate drives(nothing but), and have no issues. Why ? Probably >> because I do not run RAID. RAID is notorious for being hard on drives. >> Especially RAID 5/6. I will admit, that Seagate's reputation has gone into >> the toilette in the last 8 or so years. All their drives used to be lifetime >> warranty. Now days I think they give 3 years . . . not even as good as WD, >> or even Samsung SSDs . . . >> >> Anyway, seriously. Unless you're running a server that sees thousands+ of >> transactions a day. You don't need RAID. But hey, don't pay attention to me. >> . . >> >> >> On Sun, Nov 29, 2015 at 1:44 PM, John Syne <john...@ <>gmail.com >> <http://gmail.com/>> wrote: >> That makes perfect sense. BTW, the only purpose of a RAID backup is to >> prevent a single point of failure (like a disk failure) resulting in lost >> backups. >> >> One thing to pay attention to is the MTBF numbers for disks. I was a firm >> believer in Seagate Barracuda disk until I had a whole number of them fail >> over a few months. Speaking Seagate tech support, they explained that the >> SMART data on these disks showed they had more than the 3,000 hours MTBF and >> hence I should have expected them to fail. I couldn’t believe what they told >> me; running their disks 24 hours/day, they expected failures in 1/3 of a >> year. They were right, look at the SMART data on Seagate disks and you will >> see read write errors in the 10’s of thousands or more. >> >> After that I use Western Digital RED disks which are designed for 24/7 NAS >> applications. Looking at the disk SMART data, I see 0 read/write errors. >> >> Regards, >> John >> >> >> >> >> > On Nov 29, 2015, at 3:37 AM, c...@ <>isbd.net <http://isbd.net/> wrote: >> > >> > John Syne <john...@ <>gmail.com <http://gmail.com/>> wrote: >> >> [-- text/plain, encoding quoted-printable, charset: UTF-8, 156 lines --] >> >> >> >> Yeah, but rsync only gives you a snapshot and not a history of your >> >> backup. >> >> When I really mess up, I want to go back to the state of my machine 15 >> >> minutes ago, or two days ago. This has saved me a lot of head scratching, >> >> trying to find out where I messed up. I really like the way timemachine >> > >> > I use an rsync based incremental backup system (I wrote it myself >> > having used rsnapshot for a while, rsnapshot is OK but I think it's >> > too complex). >> > >> > I do hourly incremental backups locally to another disk on my main >> > machine and I do daily incremental backups to a remote machine. The >> > daily remote backups get thinned out as they get older so there are >> > daily backups for the last month, then monthly ones for 12 months, >> > then yearly ones. >> > >> > -- >> > Chris Green >> > · >> > >> > -- >> > For more options, visit http://beagleboard.org/discuss >> > <http://beagleboard.org/discuss> >> > --- >> > You received this message because you are subscribed to the Google Groups >> > "BeagleBoard" group. >> > To unsubscribe from this group and stop receiving emails from it, send an >> > email to beagleboard...@ <>googlegroups.com <http://googlegroups.com/>. >> > For more options, visit https://groups.google.com/d/optout >> > <https://groups.google.com/d/optout>. >> >> -- >> For more options, visit http://beagleboard.org/discuss >> <http://beagleboard.org/discuss> >> --- >> You received this message because you are subscribed to the Google Groups >> "BeagleBoard" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to beagleboard...@ <>googlegroups.com <http://googlegroups.com/>. >> For more options, visit https://groups.google.com/d/optout >> <https://groups.google.com/d/optout>. >> >> >> -- >> For more options, visit http://beagleboard.org/discuss >> <http://beagleboard.org/discuss> >> --- >> You received this message because you are subscribed to the Google Groups >> "BeagleBoard" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to beagleboard...@ <>googlegroups.com <http://googlegroups.com/>. >> For more options, visit https://groups.google.com/d/optout >> <https://groups.google.com/d/optout>. > > > -- > For more options, visit http://beagleboard.org/discuss > <http://beagleboard.org/discuss> > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected] > <mailto:[email protected]>. > For more options, visit https://groups.google.com/d/optout > <https://groups.google.com/d/optout>. -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. 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