> что за диски?

ST4000NM0033-9ZM    8шт
ST4000NM0035-1V4    2шт

> размер их блоков?

Sector Size:      512 bytes logical/physical

> куда они подключены? в RAID?

К серверу я подобраться не могу чтобы посмотреть.
sas2ircu LIST  показывает:
        Adapter      Vendor  Device                       SubSys  SubSys
Index    Type          ID      ID    Pci Address          Ven ID  Dev ID
-----  ------------  ------  ------  -----------------    ------  ------
   0     SAS2308_2     1000h    87h   00h:01h:00h:00h      1000h   3020h

[root@srv-stg-01 ~]# camcontrol devlist                                                                                            
<LSI SAS2X36 0e12>                 at scbus0 target 8 lun 0 (ses0,pass0)                                                            
<ATA ST4000NM0033-9ZM 0001>        at scbus0 target 12 lun 0 (pass1,da0)                                                            
<ATA ST4000NM0033-9ZM SN06>        at scbus0 target 13 lun 0 (pass2,da1)                                                            
<ATA ST4000NM0033-9ZM 0001>        at scbus0 target 14 lun 0 (pass3,da2)                                                            
<ATA ST4000NM0033-9ZM 0001>        at scbus0 target 15 lun 0 (pass4,da3)                                                            
<ATA ST4000NM0033-9ZM 0001>        at scbus0 target 17 lun 0 (pass5,da4)                                                            
<ATA ST4000NM0033-9ZM 0001>        at scbus0 target 18 lun 0 (pass6,da5)                                                            
<ATA ST4000NM0033-9ZM SN06>        at scbus0 target 19 lun 0 (pass7,da6)                                                            
<ATA ST4000NM0033-9ZM 0001>        at scbus0 target 20 lun 0 (pass8,da7)                                                            
<ATA KINGSTON SUV400S 96R9>        at scbus0 target 22 lun 0 (pass9,da8)                                                            
<ATA KINGSTON SUV400S 96R9>        at scbus0 target 23 lun 0 (pass10,da9)                                                          
<ATA KINGSTON SUV400S 37R5>        at scbus0 target 24 lun 0 (pass11,da10)                                                          
<ATA KINGSTON SUV400S 96R9>        at scbus0 target 25 lun 0 (pass12,da11)                                                          
<ATA KINGSTON SUV400S 96R9>        at scbus0 target 26 lun 0 (pass13,da12)                                                          
<HGST HUH721010AL5204 C21D>        at scbus0 target 27 lun 0 (pass14,da13)                                                          
<HGST HUH721010AL5204 C21D>        at scbus0 target 28 lun 0 (pass15,da14)                                                          
<HGST HUH721010AL5204 C21D>        at scbus0 target 29 lun 0 (pass16,da15)                                                          
<ATA ST4000NM0035-1V4 TN04>        at scbus0 target 32 lun 0 (pass17,da16)                                                          
<ATA ST4000NM0035-1V4 TN04>        at scbus0 target 33 lun 0 (pass18,da17)                                                          
<ATA Samsung SSD 860 2B6Q>         at scbus0 target 34 lun 0 (pass19,da18)                                                          
<ATA Samsung SSD 860 2B6Q>         at scbus0 target 35 lun 0 (pass20,da19)                                                          
<ATA WDC WD101KRYZ-01 1H02>        at scbus0 target 38 lun 0 (da20,pass22)                                                          
<ST120FN0021 B550>                 at scbus2 target 0 lun 0 (pass21,ada0)

> какой там размер блоков указан?

подскажите пожалуйста где посмотреть

> желательны еще графики нагрузки по IOPS за последний месяц, год.

https://yadi.sk/i/cgdkx8CTLUQwLg
https://yadi.sk/i/HXTBBwKtTpN86Q